Michael Gazzaniga (PhD '65), Neuroscientist and Pioneer in Split Brain Research

When there is a disconnection between the two hemispheres of a human brain, what can be learned about the basis of perception and cognition? For individuals suffering from epilepsy and other neurological conditions, what benefits can they enjoy following surgery to sever the corpus callosum, the bundle of nerves that connects the two hemispheres? These are the questions that propelled the research of Professor Roger Sperry at Caltech, who worked closely with his PhD student Michael Gazzaniga, in the early 1960s. Their pioneering analysis of how the patients responded to a variety of visual and tactile tests heralded the rise of split-brain research, a flourishing field that serves as a foundation to the basic questions of brain function. Sperry was honored with the Nobel Prize in 1981 for his pioneering work in the field, while Gazzaniga continues to investigate all of the connections between the biology of the brain and the mental processes that govern our perceptions.

In the discussions below, Gazzaniga recounts his upbringing and the impact of his father, who was a medical doctor. He reflects on his educational trajectory, beginning with college at Dartmouth, his graduate and postgraduate work at Caltech, and a formative postdoctoral appointment in Pisa, Italy, at the Institute of Physiology. Gazzaniga shares important details about the sense of excitement in biological research generally during his Caltech years; molecular biology was still in its early years, and the questions that Sperry was pursuing were related to Professor Seymour Benzer's work elucidating the genetic basis of behavior. As the beneficiary of and a hardworking contributor to, this intellectual ferment, Gazzaniga's subsequent professional career has come full circle: his first appointment was at UC Santa Barbara in the Department of Psychology, and since 2006 and his return to UC Santa Barbara, he is Director of the Sage Center for Study of Mind, one of the world's leading centers in the field of cognitive neuroscience.

In the intervening years, Gazzaniga has held leading positions in a rich variety of institutions, including New York University, Stony Brook, Cornell University Medical College, Dartmouth Medical School, and UC Davis. His career, toggling between clinical and basic science environments, represents an extension of the basis of his graduate work and the import of split-brain research both for basic science and for therapies that ultimately are designed to help people. Gazzaniga's rich legacy of service to the field includes his presidency of the American Psychological Society, advisory work in a broad range of academic and governmental initiatives, and editorial leadership of the major journals in cognitive neuroscience. As a beneficiary of Roger Sperry's mentorship, Gazzaniga has been a prolific advisor to generations of postdoctoral scholars and graduate students, who now have leading positions in neuroscience throughout the world, which is a testament both to Gazzaniga's devotion to teaching and to the blossoming of neuroscience writ large.

Despite the highly technical nature of Gazzaniga's work - and the difficult scientific, moral, and philosophical issues that arise - readers will benefit from Gazzaniga's plain-spoken nature, good humor, and capacity to convey the science in a way that is readily understandable. Like all great scientists, Gazzaniga is most comfortable grappling with the unknown, and an obvious duality to his career achievements is that his discoveries are but a window into all that remains to be known about the brain and cognition. And far from being a cloistered academic who reserves these questions within a small research circle, Gazzaniga is a prolific author and communicator of neuroscience. His books, including The Bisected Brain; Nature's Mind: The Biological Roots of Thinking, Emotions, Sexuality, Language and Intelligence; Cognitive Neuroscience: The Biology of the Mind; Human: The Science Behind What Makes Us Unique; Who's in Charge?: Free Will and the Science of the Brain; The Consciousness Instinct: Unraveling the Mystery of How the Brain Makes the Mind are a veritable world unto themselves, which bring to popular audiences the questions that unite us all, regardless of our training or background: how do we make sense of ourselves, and the world around us? It is a question that humans have always asked of themselves, and advances in neuroscience will only continue to sharpen the answers.

DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It is Monday, April 29, 2024. It is my great pleasure to be here with Professor Michael S. Gazzaniga. Mike, it's great to be with you. Thank you so much for joining me.

MICHAEL GAZZANIGA: You bet! Thanks for having me.

ZIERLER: To start, would you please tell me your title and institutional affiliation?

GAZZANIGA: Currently I am Emeritus Professor at University of California Santa Barbara. I retired this past July and am now busy at home. It turns out the day-to-day activity doesn't change much.

ZIERLER: [laughs] What about all of your other affiliations? Did you step down, for example, from the SAGE Center?

GAZZANIGA: Yes, yes. As we speak, actually, there's a recruitment process going on for the successor. Excellent people are involved, and we'll see what happens. UC Santa Barbara is very enthusiastic about the SAGE Center, and they are really very desirous of pushing it forward. That's all good news.

ZIERLER: You said your day-to-day hasn't changed that much. Does that mean you're active in research? Are you keeping up with the literature?

GAZZANIGA: What happens is, as you age into your profession, you're called upon to do all kinds of things. In my case, I have become a very active editor of the Proceedings of the National Academy and now find myself editing something like 300 papers a year. The first duty is to make the first cut and decide which papers go out for further review. For the third or so that you like, you're supposed to find an editor to help you, and then they take over the rest of the process, getting the reviews and moving the publication process forward. Basically, every day you wake up, the assignments are delivered to you. Then the second project I'm working on is another book and that keeps you always busy. The third project is that I have—let's see here— seven grandchildren. [laughs]

ZIERLER: All right! [laughs]

GAZZANIGA: There we go!

ZIERLER: Are they mostly local, your grandkids?

GAZZANIGA: Two live in Los Angeles, but three live—well, they're off to college now, and they live up in Sacramento—and two live in Boston. And two live in Chicago. Yeah. So I didn't count right there, did I? We've got nine of them! Yeah, okay.

ZIERLER: Many, many blessings.

GAZZANIGA: Many, many blessings indeed. They're all good kids, too.

ZIERLER: What's the book? What are you working on?

GAZZANIGA: It's trying to give a current and a fresh perspective on the basic phenomenon of split-brain research in humans and trying to tell it from a different angle. I want people to kind of catch the fever of it. The topic is very relevant to current discussions in the field —about how the brain enables conscious experience. I think. So, we'll see. You're a writer; it's—I'm discovering that as you get to know writers, none of them say they like it. It's hard work.

ZIERLER: No. It's awful.

GAZZANIGA: It's awful—[laughs].

ZIERLER: You like having written. The process of writing is totally different.

GAZZANIGA: Yeah, exactly right. Well said. Anyway, that leads to a full enough day in terms of my current—

ZIERLER: Your current interest in split-brain research, is this a synthesis, a capstone of your scholarship, or are you looking to the future, are you looking where the field is headed?

GAZZANIGA: To try and articulate how you see the world because of what you know is always the challenge. Whether you have the secret sauce to tell people how to think about the future—we always flirt with that, but it's rare that that's how it spins out. Other people come in and see something. You have to put down your vision, and then you kind of leave it to others to see if it's going to direct people into the future. That's a real tough one. And I think history answers that. The individual scientist shouldn't!

Neuroscience as a True Frontier Science

ZIERLER: When you look to the younger generation—assistant faculty, postdocs, graduate students—what are you seeing in terms of their interests? As they chart out the decades ahead in their career, what's the window onto where the field is headed?

GAZZANIGA: That's a really good question, and I think it's one we should all be thinking about. Just to give a few data points, it used to be that if you went off to get a graduate degree at Caltech or Berkeley or Harvard or wherever, 90 percent of the graduates went off to academic jobs. They were there because of the intellectual academic questions, and somehow they got hooked by the science. Now, the statistics are quite different. I don't know what they are at Caltech, but I do know what they are at the University of California, which is that roughly only 30 percent go into academics. There's a tremendous draw to industry for all the reasons we know about—the high tech, the money, and so forth. Also, there's this romance that there are people who are trained on data analysis, and commercial businesses have a lot of data, and they want someone to analyze it in terms of their sales and all this kind of stuff.

So, there are all these other things to do. And, the hiring of academics is slower, because there are not that many jobs. The higher education community isn't expanding its faculty at the rate that people want to go to school. There's a change there. Then the other thing is that people are drawn in by technique and technology. They like it. It's practical. They can see where it could take them. They could make money doing it. They see careers. So, the guy or gal that's just kind of sitting there questioning everything, there are not as many of them. There's a practicality to their life that I think has become more prominent in the process. All types are still around, but we're talking about the proportion shifting. There are so many things going on. I had a long discussion this week with a colleague here in Santa Barbara who told me how many kids now simply don't show up to class. One can say, oh, well, it's on Zoom, and so they're just going to Zoom from their room and sleep in a little later. That's not it. It's a much bigger number. And these are classes where there is no Zoom option, and they're not showing up. It's a stance. It's an attitude. Something's different. Higher education has to deal with it, and we're not, yet. We don't know what's going on. We don't know where this tremendous revolution that began three or four years ago of switching to Zoom plus other trends will lead. We haven't come to grips as to what the point of a university is in the larger educational landscape now. There's going to be a lot of tough discussions coming along to deal with this.

ZIERLER: I'm well positioned to ask this question; I talk with scientists for my job, and I hear a variation of this kind of a response. Whether I'm talking to chemists or physicists, engineers, astronomers—so many of them say, "If I had to do it all over again and start my career today, it would be the study of the human brain." Of neuroscience, neurobiology. Because that's where they see so much fundamental discovery way out in the future. Maybe like chemists before the periodic table or physicists before Maxwell's equations. I wonder if you reflect on that from your perspective, how you see that balance of what we understand and where the black box of understanding is in the future.

GAZZANIGA: In the last 50 years, during my career, there has been just this explosion of interest in neuroscience. It's all over. There are tens of thousands of people practicing neuroscience, and they're collecting data, and they're showing stuff, and they're showing more detail. There are incredibly fascinating and taxing technologies that allow you to do all that, from knowing the subtleties of pathways to the physiological interactions. Having said all that, none of us have the slightest idea how [pauses to touch nose] I just did that.

ZIERLER: Let the record know, Mike just touched his nose.

GAZZANIGA: That's right! How a thought becomes a discrete motor response, you can hear a lot of fancy talk, but basically, we don't know how it works. We've gone from, well, if we just study these changes at the synaptic level, we'll figure memory out. Well, that's a bust.

Alright then, if we can just understand maybe 50 cells, what they're doing at once, instead of one, we can get a better view—well, yeah, there were a few insights. But there's 83 billion and a trillion synapses doing something too. It just keeps going – 1 neuron, then 100 neurons, then 100 neurons with 100 synapses, then 10,000 neurons with 10,000 synapses. How much information do you have to capture before you have an idea of how a brain works? That's wide open. We're just at the front door of those kinds of deeper understandings.

The people you interview are correct—this is not a field that's about to wrap it up and tell you the full answer. It's still a little baby field that has lots to learn, lots to try to capture. I had a Caltech professor friend of mine recently give some encouraging news. I won't name him, but it's obvious who it will be, I guess. He was worried at one point that students used to come in and want to know about the deep questions of networks. Then they went through a phase where, no, that was too deep; they wanted to know something simpler because they wanted a job in Silicon Valley. And he says now they're coming back to wanting to know answers to the deeper questions of how layered architectures work and so forth. So, I think the real smart ones are saying, I hope they're saying, this field needs help, and we better get in there and give them some of these more complex ideas. Because we do, absolutely, need help.

ZIERLER: Mike, where do you put technology in the advances of neuroscience? How much do we now understand about the brain as a result of advances in technology, and how much is it just good ideas coming along?

GAZZANIGA: I'm a big believer in the good-idea philosophy. The technologies are revealing things. There's an old joke that used to float around—let's see, how did it go?

9W. That's the answer; what's the question? People cast about, and say, "Well, is it the major route of New York City?" That's Route 9W. It turns out the question is, "Do you spell Wagner with a V?" "Nein. W."

ZIERLER: [laughs]

GAZZANIGA: It's a great story and a great lesson. People come up with these elaborate demonstrations and justifications for a new technology that shows some pattern or results. You can say, "Well, that's the answer. But what was the question?" It's fundamental to real, profound, world-changing scientific advancement. That's what everybody should keep in mind. There are these vast correlational studies that find things no one could have imagined before.

Great, you find it, so now what do you know? The answer to a question no one really cared to ask. Not a step towards the answer to an important question, a fundamental question. People are very much aware of this, but you've got to make a living, so you go for the local, practical result. The system is biased towards the practicality of getting a reliable result about something. The person who wants to sit around and say, "What does that mean?" is going to have a harder time finding a job in the short run. There are all those issues that boil up. An old guy like me can say that. If you're in the mix, however, it's hard to make [laughs] that one of your prominent themes.

The Big Consciousness Questions

ZIERLER: What about the more specific question of consciousness? What do we know already? What are the big questions that remain?

GAZZANIGA: Well, the original question —what is it — is still sitting there as pregnant as it has ever been. People have plenty of thoughts about it. We just lost, as I'm sure you know, the philosopher Dan Dennett, who thought about it for 50 years and made a strong case, and a compelling argument for many, that it's just an illusion. It's what the brain does; get over it. He said once: If you explain all the things that you think you can understand about brain function from memory to motor control to a feeling, whatever it is, you're going to have the explanation and that's it. There's no special conscious box in the brain, there's no special process that gives rise to this phenomenon. A pocket watch with all of its intricate gears in the end tells time. Try to find time in the watch. That's a very studied and well-supported position by some. Then there's other people who draw on mechanistic insights and network structures, and they say, "The information has got to flow here, and then it flows there, and then goes over there, and then something happens."

The deeper view is, we just don't know. We don't have a handle on it yet. So, what people do, and certainly in my contributions, you don't go too deep into that question. You just say, well, let's do things. When does it happen? What brain lesions affect it? You just start studying it as if it's something, and you ask reasonable questions and hopefully illuminate the underlying mechanisms of how the brain must be doing its tricks. But you don't come up with the answer. I would say all these approaches have not yet done that. We all have views, and I wrote a book called The Consciousness Instinct, trying to point out a number of things about it. But did I come up with the answer? No! I told you a lot of things about it, though.

ZIERLER: When science falls short in helping to explain some of these big questions—for you, is there value in non-scientific approaches, in thinking about philosophy and even perhaps spirituality?

GAZZANIGA: I don't know how far out you are on that one. When you speak of spirituality, what—? You know.

ZIERLER: The notion that there is not strictly a material perspective to have here.

GAZZANIGA: Yeah, yeah, yeah. I tend to go to sleep with those explanations. I mean, it's a hard problem. It's absolutely hard. And we all are our personal own authority on this topic. Right? We do have feelings. We do have this state of mind that feels completely real and robust. Like if I could, this very topic is what I'm trying to capture in my new book. I won't tell you the title of it. I've got a title, and I've got a first chapter.

ZIERLER: That's a book! You're on your way!

GAZZANIGA: It's started! Can't back out now! But you put your finger on the question. We're all looking for new approaches, new perspectives, a new insight on how something at one level can work to build the next level, the next layer. How does that work? How do we think about it? I'm a big fan of people like your professor at Caltech right now, John Doyle. That's what he puzzles, and he has done it with brilliance and leadership—how do you get these layers, and what are the protocols between them? How do you even think about it? How do you apply that to neuroscience? He comes out of engineering and control and dynamical thinking, of course. That's a big, meaty question, and people are just beginning to gear up for that.

My commitment to that is that one of the things I did get established here at UC Santa Barbara is a graduate program with that as the goal. Dynamical Neuroscience, we called it. People come in from Engineering and Biology, and they take common courses together, and they're mixing it up. Interestingly, it has kind of risen to the top. The program and the kids that apply to it are really the top kids. The professors know all this. They feel it. I feel if that's getting communicated to the real smart kids, then the next era is going to be full of invention. I guess in a way, it's up to the academics who run these institutions to let it happen, to let the line out here.

ZIERLER: I want to get to some more specific questions about the topics that you've pursued over the course of your career. Perhaps let's start with anatomy. Is everything related to the brain, in terms of what you've done? Are there aspects of brain-body interface that you've worked on? Are there aspects of research that you've done that have nothing to do with the brain?

GAZZANIGA: How do I answer that? One of the big ideas that came out of our research was the notion of this special thing in the left hemisphere of people we called ‘the interpreter.' It's built on something we observed from these very special split-brain patients. In most people, the right hemisphere doesn't talk. But in these folks, we found out, after we got into it, the right hemisphere could do other things that either the left hemisphere could not or did not know about, and of course the left hemisphere is observing this. And—that's weird, you know? How does that work? What we discovered was that the left hemisphere instantly takes whatever the right hemisphere experiences (whether it was an emotion or an actual behavior) and incorporates it into a storyline. There's a story that's ongoing all the time in the left hemisphere that explains what you're doing and why you're doing it. The left hemisphere observes what you're up to and then makes it all sensible with respect to the ongoing story. When you think about this and the years of experiments we did, you just realize that—maybe at the heart of consciousness, it's a story that we've told ourselves. And it's ongoing. We live it every day. We wake up. We add to it. We forget parts of it. We do this. And when we forget parts, we remake up other stuff. We invent other stuff to fill in. That's why we're full of false memories. I used to joke, "I like false memories. Some of my best memories are false."

ZIERLER: [laughs]

GAZZANIGA: And you can do studies showing this kind of stuff. So, I would say you have to consider the story itself as another level, another layer in the system. It's not just the brain areas experiencing emotions, noticing sensations, controlling actions. It's the way all those things are spun together into a narrative. How we would represent that vis-à-vis the actual brain mechanisms that are chugging along to produce it? We can't tie those things together yet. The story is real. The brain mechanisms are real. We just don't know quite how they get stuck together. But they do, in some way, I suppose. Over the years there has been a lot of research by people who try to find this little man in the machine that's making all the decisions, that's calling the shots. Did you ever see the movie Men in Black?

ZIERLER: Sure.

GAZZANIGA: They open up the head, and there's a little guy in there pulling the levers?

ZIERLER: [laughs]

GAZZANIGA: Yeah, that's kind of what our baby model is. Dan Dennett used to show a film clip for Men in Black all the time in his lectures to make the point. He says, yeah, that's just not the way it is, folks!

ZIERLER: [laughs]

GAZZANIGA: There's a ton of experimental psychology and neuroscience which now goes along with this. You have these decision mechanisms, and you have all these layers of memory constraints, and you have these networks adding this and adding that. It's a decision process and a network, and on and on and on. We can say all those things, but there's still no book we can go to that tells us actually how it gets done. There's no manual or knowledge depository. We're still lacking that. That's the challenge.

ZIERLER: I asked about ‘beyond the brain.' Within the brain, what are the areas that you're focusing on?

GAZZANIGA: A question that has always fascinated me is how people attach feelings about specialized capacities. From an evolutionary point of view, if you look at all the incredible cognitive skills that we humans have, you could argue that many are adaptations. They've been built in over millions of years. They've been ways the organism can solve a situation to enhance survival. These things are all over the brain, distributed in various ways. When we're using one of them, we have a feeling about it. So we have a feeling about a specialized capacity – we feel an emotion over some cognitive ability we have. Is that what we're talking about when we're talking about conscious experience? If one can figure out how that works, you would be closer to understanding what we actually mean when we're consciously aware of one of these capacities. That kind of thinking. You're always back in there trying to think about these fundamental associations. You're alive and you're aware of it, that's all true, but how does it work? Caltech has a real opportunity, because of its environment here. I'm a firm believer that the engineers have it right when they say, "If you can't build it, you don't understand it." Man, that's a hard one! It's so funny, too—when you give a lecture and there are engineers and there are basic scientists, the engineers give you the hardest time.

ZIERLER: [laughs]

GAZZANIGA: "Well, what do you mean by that? How can I build—?" Oh, God, give me a break! I'm just trying—you know. And the other guys are thinking in their abstract models and it's a lot of fun. Caltech has got both of those types, full force, right there, people thinking from an engineering perspective and from a deep theoretical basic science perspective. That makes the place special.

ZIERLER: Everyone is talking about machine learning and artificial intelligence these days. I wonder if you see these advances either as particularly promising as a research tool or even philosophically in understanding what learning and thinking means.

GAZZANIGA: The prudent answer is—not to answer that, because I have no idea. The old metaphor—Big Blue beat Garry Kasparov. Big Blue beat him for sure. But the story was that it wasn't a mental system that toppled Kasparov. It was something that could do all these multiple calculations at such speeds that, of course, it will beat the human brain. So what? So that kind of thing already exists and they're all over the place. But are they going to take on that essential feeling of being human and morality and all those sublime states of human existence?

The advocates for this view say yeah, it's going to do all that, just be patient. In some sense the question is, we've got a whole other way of making another human, and it's really fun. What are we doing this for? [laughs] Why do we need more humanlike things? Maybe that one should be put aside.

Just look at the revolution in deep learning and ChatGPT— all that. There is no question they are going to be great tools at solving things that humans can't solve, like what the structure of a new protein could be to block some cellular process. That seems to be a hugely important field that's coming online now. We just couldn't do it. We humans, no matter how many little experiments we did, couldn't dream up the crazy three-dimensional configuration. But now we have it, we have exactly the structural information needed to do important biological experiments, to test how these proteins work. That's incredible. If these new toys are used in that sort of technical way, it's obviously going to be fabulous. If we've built a monster that is going to work in some bizarre way—it's something we're going to have to deal with.

It Starts with Psychobiology

ZIERLER: A nomenclature question, and to the extent there's meaning behind the words, do you think of yourself more as a psychologist who does neuroscience, or a neuroscientist who does psychology?

GAZZANIGA: From my graduate days at Caltech onward, the program was called ‘Psychobiology.' In those days, you just went to work in the lab.

ZIERLER: [laughs]

GAZZANIGA: You took some course—I forget what it was—a couple courses—and then you had a few qualifiers you had to pass. Mostly you just studied on your own and learned stuff as needed. I remember for one of my exams I had Roger Sperry and A.H. Sturtevant as my examiners. Sturtevant's test was—he handed me a box full of insects impaled with pins in them, and he told me to name them. What the hell? Genus and species—you know, the whole bit. I got 49 out of 50. Then Sperry asked me a question about the development of the otic vesicle, the auditory system. And I was so undone. It's a standard freshman question. It was a softball, from my mentor! [laughs] I got so frustrated.

But fortunately, students were mostly evaluated by what you did in the lab. You went to work right away, and you did experiments. With the psychobiology group, in Sperry's lab, we had neuroscientist postdocs, we had psychologist postdocs. During my third or fourth year in, I forget which one now, I had the thrill of Seymour Benzer coming to spend a year with Sperry as he was getting his neurobehavioral work going. He had the office right across from me. And at Caltech, everybody is equal and everybody is just shooting the breeze with these famous people. Nothing is made of the difference in class or field or who's won a Nobel Prize or what-have-you. So, there were psychologists, there were neuroscientists, and whatever came out of that means you listened to both sides with intensity. I suppose throughout my adult life, I have, just because of the nature of the work of the split-brain behavior and all that, found myself affiliating more with psychologists.

Sperry loved psychologists. He thought they were by far the more profound thinkers, which shocked me. Here we were in the Biology Department, but he was totally aware of their value. Throughout life, I became very close friends with a number of famous psychologists, and each one was a treat, to see how their mind worked. It is funny that as you get to know people that are famous for something and they know you, you rarely talk about any of that. You're on a level field when you're talking about whatever is current, in the sciences or in cultural news and everything else that pops up. There's a notion that people sit around and talk about who understands less or more about the esoteria of quantum mechanics. That may go on somewhere, at some level, and I'm sure it does, but when you're just talking with a colleague, even though there may be an age gap, you've sort of won the ticket to be there. And now that you're there, you're not going to talk about that stuff. You're going to talk about—what's current. It's a conversation they wouldn't have with anyone else. It's just the two of you talking, here, right now, about life as it's unfolding. That was always an exciting part of those friendships.

ZIERLER: Have those distinctions changed over the years in the fields that you represent, what it means to be a psychologist or a neuroscientist, posing the questions that you're posing? Have those boundaries or the kinds of questions changed?

GAZZANIGA: That's a really good question. [pause] It would be interesting if we'd had this conversation, say, before COVID, because what was it like? We're only talking three or four years ago, but now, post COVID, there are all kinds of discussions about how we have to reconstitute social events for interaction and discussion and colleagueship and all this stuff. I don't remember that as such a deep issue before, but it is now. There's an isolation, a happiness with Zoom, that is very disruptive.

We just had a speaker here at UC Santa Barbara, a very well-known person. Now what happens, because there is Zoom capacity for the lecture, is that the meeting-room—and this is for visiting people, not like the classroom example I gave earlier—is half as full. I tried to point out to people—I said, "We're here to benefit from the speaker, but it's also our time to represent who we are, to them." Because they're traveling the world, and well, what is going on in Santa Barbara? And people say, "Well, no, the other people were home in Zoom, watching it." That doesn't work. The chemistry of the room, the feel, all the cueing that goes on in interpersonal relationships, it has taken a hit. Whether we're just going through some phase now and we'll get back to that other one or not, I don't know.

ZIERLER: Communicating to the public has always been very important for you—in your presentations, in the books that you write. Why is there that importance, that need for you to sort of communicate these things beyond your scholarly peers?

GAZZANIGA: Beyond the fact that I had six kids to send to college and what a bill that is!—there's a real enjoyment to it. Let me tell you the good—from my point of view. Maybe I'm doing a public good, but there's a real enjoyment in explaining some scientific finding to a very smart person who may be a banker, or a geologist, or dare I say even a physician who is in clinical practice and doesn't have the time to really think about the implications of a behavioral result. A businessman, a salesman. They bring to it—they're interested in what you're saying. This is the point. When you go give a public lecture, the people that are there are there for a reason. They're kind of interested in this. And then if you can successfully tell a story, that's very gratifying. It's fulfilling to me. So there's that part of it. The other thing is that it wasn't too big a switch for me, because I kind of write in a conversational style anyway. So, to have someone say, "This ought to be a trade book, give it a shot"—and so I did. Then I wound up writing four or five of them along the way. I also wrote textbooks. I also edited these big summer institute reference type books, which is another kind of academic task. So, it's fulfilling.

Applications and Fundamentals

ZIERLER: Have you always thought of your work as rooted in fundamental research? Is it all about just discovery? Have you ever thought about its work in its translational or applied value?

GAZZANIGA: How I'd try to capture at least an aspect of that question. About 20 years ago—has it been that long now?—yeah, maybe—yeah, 20 years—oh, geez—I was asked to serve on President Bush's Bioethics Council. That turned out to be an eight-year gig, as they say, which meant every six weeks in Washington. The first part of that was a very tense moment in biomedicine and politics, where—blastocysts and cloning and all that was on the table.

Biomedical cloning was real now and should it all be shut down? There was the embryo question and what is life, and when does it start? So, 18 of us from all over—lawyers, ethicists, liberals, conservatives went to Washington, tried to hammer this out. It was run by a very well known, very classy guy, Leon Kass from the University of Chicago. It took a lot of energy, preparation and work. So, you realize that because everything takes time, and there's only 24 hours in a day, when you take on one of those things, there's a cost. It probably means you're not going to be as closely involved in that experiment that's going on in your lab. You're going to know all about it, of course, but those balances are going on all the time. To some extent, those balances are going on in every professor's lab at a scientific institution, because of the horrendous demand on them to raise money for their research. Constant. Constant burden. Then the administration of those grants once awarded. And, of course, all the editorial duties.

A colleague of mine once wanted to write a book called Thirteen Minutes. That's what he calculated—he kept count. He had a stopwatch on his desk, and every time he started thinking about what he was supposed to be thinking about, he started the stopwatch. It turns out, it was about 13 minutes a day. The rest of the day was doing all the other stuff you have to do. That factor has only grown. It has only gotten worse. I have a—well, I shouldn't—I have a daughter that has just started in the business at Harvard Medical School, and—jeez! The amount of time that you have to spend on the science funding is just—it's just unbelievable.

ZIERLER: A question about science funding—you have a long history with NSF, with NIH. What are the broad trendlines in government support of basic neuroscience research? When did they get involved, and where is it today?

GAZZANIGA: I think it was around 1970 that the Society for Neuroscience was born. It was put together by the leaders of the field. They had a first meeting in Washington, and many people were involved in putting it together. They dubbed it the "Society for Neuroscience." People had been calling it all kinds of things—psychobiology, physiological psychology, all kinds of names. It all snapped together under this one big umbrella—neuroscience—and of course it has been this monster ever since. Then in 1989, there was the Decade of the Brain, which had been one of George H.W. Bush's initiatives. Then, later, there was the Brain Initiative that Obama put forward. All these things along the way have been trying to get greater support for brain research and neuroscience. And they all have. They've all contributed.

But it's not easy. In fact, it's so competitive that when, say, the University of California now hires an assistant professor, it used to be that they'd give them a startup package of a particular size, and then they assumed within a year or two, they'd have their R01s and be funding themselves. Now, the picture is quite different. The startup packages have to be quite large, because the university understands it would be sheer luck if they start bringing in R01s before five years. Why? Because of the competition, because of the different way NIH thinks about what should be funded. They want surer bets than risky bets and so forth, and there's a whole story there. People have told me that's one reason the participation in academic jobs has decreased. Because if you go off and work at Google, you've got your budget the next day, and you go about your work. You go off and work elsewhere, and you've got to raise money first.

ZIERLER: What about the world of private benefactors? What has been their interest in supporting basic neuroscience research?

GAZZANIGA: Usually, a family is focused on a particular disease, such as Parkinson's disease or dementia. Those are the family groups that help to increase funding fast since these people have a natural interest and concern, and they want to speed things along. Cancer research is another—kind of an easy one to explain to folks why it matters. But if you tell somebody, we're studying how neurons allow you to combine color and shape so you can see a triangle, well, how is that going to help their sick loved one? Huh? What am I paying for? Well, you're paying for something very fundamental and hard conceptually to figure out. Oh, well, okay, they say. Come back when you've sharpened that up a little bit! It's a different ballgame.

ZIERLER: You mentioned disease. Does your research impact or is it relevant to the all- important questions surrounding neurodegenerative diseases?

GAZZANIGA: Not me. It used to be—this goes back 50, 60 years—at the end of your NIH application, there was a section called "Significance." All of us used to just pass around these boilerplate paragraphs about this long: "Well, we hope to solve"—cancer, or schizophrenia, or neurologic disease with this research. Period. Oh no, that doesn't work anymore. You have to really fit it into a practical payoff. I understand that. It may be that for real basic science research now, you go over to NSF. The problem with NSF is that the grants are a lot smaller, more focused, and so for big expensive biological laboratories, the funding is not as great. For real wild stuff, you try to see if places like DARPA are interested, because they have big checkbooks. But they can cut you off faster than you can say hello because they don't think the research findings are getting at the problem that they're particularly interested in. Every major lab director knows all of this. They're constantly churning. Then occasionally there are just benefactors who come in and get it, and say, "We get it, we understand this, and here's the check."

ZIERLER: Do you have any perspective or unique insight on why Parkinson's and Alzheimer's and dementia more generally, they're just so problematic in terms of understanding their causes, coming up with therapies or even cures? Why have we made so little progress in these areas?

GAZZANIGA: I have friends that can answer that question for you. All I know is that there is tremendous support for those people working on those problems. For example, the Michael J. Fox Foundation has given major impetus to all kinds of work on Parkinson's disease. That's great. But why is it so difficult? [pause] Let me just give you an example of why it's so difficult. As we age, and everybody knows this, you begin to have anomia. What is anomia? Just—can't find the noun you're trying to think of. Proper name anomia is when you can't find a person's name—you remember it's Uncle Harry, but wait, what was Harry's last name? Or you're trying to think of somebody from your class in school, whatever it is. This inability just goes up and up and up, with age. It gets more dense. So, then you also realize that because you can't think of the name and are frustrated by it, you do a paraphasia, you talk around it, and later, when you don't need it, boom, it finally pops up. There it is! You say the name. How does that work? What is the organization of the memory system such that that's a feature of it?

The aging process, the way I like to think of it, which applies to Parkinson's, dementia, all these questions you're asking, is a gradual deafferentation of the system. Connections in the brain are dying off, the vines that creep between cells are cut back, and the inputs aren't as strong. Maybe the tonic level of neural networks has gone down because of this random cell death that goes on with aging. I don't know what it is. No one knows what it is. But you become acutely aware of it, as you age. People stop doing things because they just don't want to be put in the position of not being their former self, of not being able to recall all the specifics of an experiment, all the specifics of relationships, all the specifics of anything. You have to go back and get bigger handles on what it is you have to offer in a remembrance.

Neuroscience Prehistory

ZIERLER: Let's do some deep history of science. Thinking about Roger Sperry, about your graduate work, what is the prehistory of split-brain research? What are the scientific foundations upon which split-brain research exists?

GAZZANIGA: A way to look at it is—the first sort of surgical intervention of people with epilepsy came actually in a rather large series of patients from the University of Rochester in the 1940s. They were written up by a neurologist named Andrew Akelaitis. He studied patients with full and partial surgical re-sections and all that, and he didn't find anything. He just concluded, "Ah, there's nothing wrong with these patients." Then there is a well-known clinical syndrome called callosal agenesis, babies born without the callosum (the connection between the left and right hemisphere). There had been light work on that. Really there wasn't any sort of split brain, interhemispheric breakdown that is so famous now. Didn't seem to be a big deal. That was kind of going on in the background.

Then I think around 1949 or 1950, Roger Sperry, with his student Ronald Meyers, started asking the question: "Well, how does information from one hemisphere get to the other?" You've got this big fiber pathway, the callosum. We kind of know roughly the anatomy. If you cut that thing, there's gotta be something going on there. So, they started in. They started out on cats. They first had to limit information to one hemisphere. They figured out how to get into the bottom of the brain and split the optic chiasm, where information from the eyes gets mixed. They found if you split it down the middle, the information from the right eye only goes to the right brain, and the left eye goes to the left brain. They technically figured out how to do the surgery and did it. Then after that surgery, they cut the corpus callosum and basically found the split-brain story in cats.

Then the next move was to do that in primates. Another couple of guys who came through the Sperry lab, Colwyn Trevarthen, followed by Mitch Glickstein, did all that primate work. That was very exciting. I think Sperry coined the term "split brain" preparation in those days. That was great. How I entered the story was between my junior and senior year at Dartmouth College, I had written to Sperry to ask him if there was any chance I could hang out in the summer. Because I lived nearby, I could easily drive over to Caltech for a job. He said, "Sure!" My intent was to go out and work on nerve regeneration, because that's what he was really famous for at the time. He did incredible work on nerve regeneration. Well, nerve growth. How does the brain organize itself? Is it selective or not when it makes connections?

I got out to the lab, and everybody was buzzing about this cat and monkey work. Oh my God! I learned about that so fast. So, I had the idea of, well, what would happen if we had a temporary split brain? I had the idea that maybe we can put half of a rabbit brain to sleep, then teach the other side something and then put it to sleep, and then see if the memories of the learned task transfers, and all these kinds of things. So, I started working on that. I had to work in the hallway of Alles Hall, because all the labs were full, and I was just this kid coming in for the summer. I finally get the prep all ready—and I'll never forget this, of course—I get the rabbit hooked up to the EEG machine. I have catheters into its carotid artery. I've got the whole thing going. Linus Pauling walks by and says to me, "What are you doing!" I said, "Well"—I go into this whole thing, and what I'm doing. He looks at me, he sees the EEG machine, the squiggles and everything else, and he says, "You know, maybe that brain is like a bowl of jelly, you just shake it and you get those wiggles. You better try that first before you give it the"—completely just tries to shoot the whole thing down. It was in a positive way, but it was like, "Have you tested all your assumptions here before you're going for this home run experiment?" [laughs] I'll tell you, that was a lesson I learned! If you can imagine. The setting was—unbelievable. I still tell people the story—Pauling had the office right around the corner from Sperry. Down the hall was Sturtevant. A floor or two below us, Max Delbrück. Feynman used to come over all the time because he was interested and walked through and asked questions. Come on! And probably the best part of it is, as a student, you weren't fully aware of what a ridiculous [laughs]—

ZIERLER: [laughs]

GAZZANIGA: —thing you were in the middle of! After the fact, you go, oh my God, what a little bit of luck to have been there. Anyway, so then I went back to Dartmouth my senior year, and I had the idea that, well, maybe we should try to test the patients in Rochester. That ended up not working out. But then, that next summer I got into Caltech, and soon thereafter came the first patient (Case W.J.) that Joe Bogen had worked up at White Memorial Hospital.

Sperry said, "Okay, start tests." He just gave it to me, I almost think it was because everybody else was busy. There had been a previous experience where a callosal agenesis (a congenital absence of a corpus callosum) case had come through and they couldn't find anything. Bogen's patient was probably a long shot anyway, so, give it to the kid that just came in. I don't know if that was it or not, but anyway, I got the assignment and started the process for five years —the best five years of my life—working it out, at Caltech.

ZIERLER: In the prehistory of the split-brain research, were there theories about why the brain was split in two?

GAZZANIGA: Way back in the early 1900s, there was a German neurologist, Hugo Liepmann, who wrote a monograph on it and made illustrations about how there ought to be something here, but nothing more came of it. It came down to the fact, going back to your psychology and neuroscience points, you needed to know how to do the tests. You had to be knowledgeable about the neuroscience underlying the pathways, to know what kind of tests should work. When you present information to people, they see it with both eyes or they hear it with both ears. The signals get mixed before they get to the cortex, so the right and the left cortex get information from both sides from the start. You've got to lateralize the information to one hemisphere, if you want the experiments to work. How do you do that? Well, you get people to visually fixate on a point on a screen, and then quickly flash the information to one side or the other so they can't cheat and move their eyes. In that way information to the left of the fixated point only goes to the right brain and information flashed to the right of the fixated point only goes to the left brain. All this stuff that we did right there at Caltech. Certainly, the modern story about the two hemispheres started right there in Alles Hall. There's no question about that in my mind.

ZIERLER: What about the role of evolution? How is evolution relevant for thinking about how the brain developed into its split regions?

GAZZANIGA: A number of years ago, I wrote a paper on this—"Cerebral specialization and interhemispheric communication: Does the corpus callosum enable the human condition?" The notion was that with the corpus callosum, you only need to have a specialized capacity in one hemisphere, because the specialized system could be communicated to the other, through just networking. So, you didn't need to build two language systems. You didn't need to build two specialized visual systems, two—you name it—theory of mind systems, for example. You only need one. That gave rise to more cortical space for more adaptations to be captured through evolution. The broad distribution of specialization was made possible because you had twice as much cortical space to get it done in, since you only needed one of each system. Now, there are all kinds of subtleties and nuances with this, because there are some people with bilateral language, very few naturally, some people with bilateral this and that. The vast majority of people are lateralized and specialized, and the various systems are distributed all over the place. So, that's what I think. As Steve Pinker observed years ago, humans do not have fewer instincts than animals. No, we don't. Humans have vastly more instincts. We just don't call them ‘instincts.' There are always automatic mechanisms going on all the time, guiding our behavior. Stuff in our brainstem, stuff in our spinal cord, stuff in the nervous system of our gut. All those nervous systems know what to do, without our conscious help. They're all adaptations in there somewhere. Some network is responsible for them. You don't have to use cortical space to get that all done. You certainly don't need two of them. More space to do more things means you can do more interesting stuff. That's how I think about it.

ZIERLER: What does a laboratory environment look like for you? Are you getting your hands wet and dirty, as they say?

GAZZANIGA: Oh, not anymore, no. In some sense, the most neurologically interesting time in my career was the ten years I spent at the Cornell Neurology Department, in New York City. There, you do rounds every day. When I arrived [laughs], the very famous chair of that department, Fred Plum, just said, "Okay, you're our neuropsychologist." This was before there were all these licensing requirements for psychologists. No, just, "Come on. Come on rounds with us." Pretty soon, Plum just said, "You're doing rounds. I'm going to Hawaii." I said, "What?" But soon enough, you put on a white coat, pretended you knew what you were doing and after about a year, I did know what I was doing. And it was fascinating, because every room had a patient with a different disorder and a different symptomatology. Then there were many times when, because I knew the experimental psychological methods, I could reveal something to the six extremely talented medical residents that they had totally missed because they had not thought of it from an experimental psychological point of view. They were teaching me and I was teaching them. So, it was very fruitful—and together we put out a number of papers on patients with various kinds of disease types that were illuminating. The rich variety of disturbances of consciousness that you can see on a neurology ward is, to this day, riveting, for sure.

I can remember during that time period, we did a lot of what's called sodium amytal testing, which is where one hemisphere is put to sleep but not the other, like I was trying to do in the rabbit earlier. The surgeons were trying to see if the speech center was where it was supposed to be. If they were right-handed, it was supposed to be in left hemisphere. If left-handed, it was more likely be in the right hemisphere. Yet there were always lots of exceptions. The surgeons were going to have to go in and cut out a tumor, and they didn't want this to be the patient that had the speech center in the wrong place. They didn't want to take off too generous a portion of the brain to keep them safe from cancer and accidentally make the person aphasic. So, they used to do this preoperative testing. We did any number of those tests. But I want to tell you that the experience of you, a fellow human, in a room where you're monkeying with someone's consciousness, is just—it's—it makes you sweat. You know what you're doing, and you know that you're tampering with a fellow human's conscious state. And then you see it. The old test we used to do was to ask the patient to hold up their hands above their head. Then the anesthetic line was fed through one of the carotid arteries and the anesthetic was injected and it travelled up to the hemisphere on the same side as the injection. As soon as the anesthetic hit that half brain, bam, the opposite hand would go down. Meanwhile the other half brain was completely conscious and awake and could palpate objects in the other hand. We did all kinds of experiments. But then, two minutes later, anesthesia would spread to the other half of the brain, and then both sides —out like a light. The point is, when you're impacting conscious states like that, it's riveting and humbling and deeply thought provoking. Now we were studying conscious mechanisms in many ways. First, we had the Caltech patients, and then there was also another whole set of split-brain patients we studied. Throughout the years, we always had visiting scientists come and do experiments. Every one of them was stupefied by actually being in the presence of where these things were going on. Because it's, it's powerful. We're getting at something here. We always knew it and yet were constantly asking ourselves, are we doing it right? How can we—? Then of course everybody thinks of 13 other things they want to do, and all that.

The Clinical Perspective

ZIERLER: Operating in a clinical environment, how did that influence your research?

GAZZANIGA: I think it gave rise to deeper ideas about what you were doing and how it impacted the human condition. The whole conscious, unconscious realm —we all know of and talk about it. But to start seeing experiments that reveal it was powerful. I'll give you an example. If a patient has a right-sided lesion, how it works is they can ignore or neglect the opposite visual field. Not blinded; they can technically see it but they basically ignore it. So if you flash a picture—say you put an apple here and an orange there, they'll call the apple because that's going to their left brain, which does the talking. It's not asleep. Or, it's not affected. And this orange over here, those images go to the right side, so they won't name it; they ignore it.

They just say, "I saw an apple. That's it." That's the basic phenomena of neglect . So we decided not to ask them if they see it. Instead, we asked them if the two things they saw were the same or different? [laughs] This is an experimental psychologist in the clinic. So the patient, all they had to do after the flash of the stimuli, was to point to one of two cards: "same" or "different." If they were totally ignoring the orange and it wasn't getting processed, they wouldn't know if the fruit were the same or different; they'd just be guessing at the level of chance. Well, they got most of them right. Even though they couldn't name what they saw going on over here on the left side.

This meant that at some level, this information was flowing through cortical circuits but outside the realm of consciousness. Some part of their brain knew there was an apple on one side and an orange on the other. There wasn't visual problem. But in terms of talking about it, it was being decided upon elsewhere, a high-level decision could be made about it. The patients were unaware of all this, except for the final part, push the right button here, same or different. So that opened up a whole way of studying and looking at how you could calculate the unconscious processes that are involved in everything we do. As we sit here and talk together with each other, 99 percent of everything that is going on here is done outside of our conscious awareness. It's the brain working. We want to study that, too. We've got to study that if we're going to understand the whole process.

So those kinds of experiences combined with getting to know George Miller, the great, great experimental psychologist who worked across the street at Rockefeller, made for exciting times. One day, I said, "So George, why don't you come on rounds with me?" Right across the street, 200 feet away, there's New York Hospital with its neurology ward. He says, "Oh, okay." So, we go on rounds and see all these folks with aphasia or neglect or memory disorders or dementia, everybody. There was a garden of disorders. He said to me afterwards, "You know, those patients, just sitting there in the neurology ward, provide what experimental psychology tries to do. What experimental psychology tries to do is present things so fast or with a certain kind of frequency so that normal brains make errors; we try to create those problems, by the nature of the way we present the stimulus. You have them sitting there, all done for us!" And now we're going to figure out how that works. He was just over the moon—and he became a huge fan. He was 60 years old at the time and had never seen a neurologic patient. That became a big part of cognitive neuroscience, which we went on to help develop and now, of course, thrives.

ZIERLER: You see the term "cognitive neuroscience" associated with your career in so many different ways. How does "cognitive" modify "neuroscience"? What does that mean?

GAZZANIGA: It means that you are studying what are generally called cognitive mechanisms. Language. Various forms of memory. Problem-solving capacities. High-level abstraction processes. You can go on and on and on. That's the field of cognitive science. What happened was that when George and I got to know each other, Rockefeller University served a social role, sort of like Caltech's Atheneum. They too had a faculty club and one could stop there after work and have a drink, and George and I did that frequently. We'd be talking about things, and we realized that cognitive science didn't have a biology—and biology, which we meant neuroscience, didn't have cognition in it. Biology was studying low-level reflexes and behaviors and rats running in mazes, and none of this had to do with thought and the underpinnings of conscious experience. At the same time, cognitive science was studying thought and perception, yet with no idea where or how in the brain those kinds of things were happening. So, we put them together.

George and I cooked up the term ‘cognitive neuroscience.' Then we obtained funding for it through the Sloan Foundation. Later on, I started the journal, started the Society, started the Summer Institute, and we were off to the races. So, it was just a realization. And I think also— lots of things were happening, then, to go back to your earlier points about technology. It was just then that brain scanning was coming in. The first CT scan, which was pretty exciting, but then when MR came in, oh wow, that was extremely exciting—and then when functional imaging—you know, it just took off like wildfire. Now we had a technology for understanding the living brain in action. That, combined with other early people who thought, well, we can—by just lifting electrical signals off the scalp, event- related potential work, as it became known, we can study correlations of that and maybe track information through time as it goes through the brain. So, all of a sudden, there were all kinds of ways of thinking about how the human mind does its tricks. And we should recognize that we have more new tools now, to do these things. That's how the field got going.

ZIERLER: You're a builder. Whether it's journals, institutes, societies, why have you found it always so important to create these gathering spots of scholarship?

GAZZANIGA: Because I see the result. There's the critical conversation. The room where, all of a sudden, the right people are in it. The magic that happens in those situations just doesn't happen otherwise, or you're not aware of it anyway. And, I am an impatient person. I get bored with what I just did and want to do the next thing. That may give rise to a—I've often thought that maybe if you're cursed with the boredom [laughs] thing, that may contribute to laziness. I've often thought, why couldn't I play the piano better? It's simple. I learn to play alright and then I think, "Well, I've got the idea here. That's enough." I'm bored with the process, so let's just go hear somebody who knows how to play it better. [laughs] And it's also fun. It's fun to get things off the ground, putting them together. Cutting deals that other people pooh poohed—I could tell you, with each one of these projects, there was lots of resistance.

People said, "Don't do the journal." Major people. "Don't do this thing." All the big fancy reasons as to why. And then you just do it. And it just—well, yeah—it turns out there are actually a lot of people who wanted this journal, or this book, or this society. It shows that the sense that the project was needed was well founded. So it worked out. After I had a couple successes, people started asking me to do things. There were a few I didn't do, because I wasn't that deeply committed to the overall goal. But if it's fun, and worthwhile, it's a great combination. Then when it's no longer fun, it just becomes routine, hand it off to somebody else and you go try to do something else.

ZIERLER: Does cognitive neuroscience feel like a mature discipline now?

GAZZANIGA: Yes, but to tell you the truth, I think it also has a long way to go. And it will come by successes, by real surprising insights on how the brain may work. They will be incremental, of course, but there will surely be some real tantalizing discoveries. Cognitive neuroscience now, I would say, is a fifth to a third of most psych departments throughout the country. The idea of not having a biologic understanding or a physical dimension to a psychological process is, "What? No. We're living in the twenty-first century. Of course you've got to have that." There were battles getting in the front door. There was the classic psychologist who just says, "Oh, we don't need to know anything about the brain." We need to know how and when you rotate this square, and it does this, and then people do that—and that's going to be our level of description. We've got to get that right. That's all true. But, there's a new—there's a new guy in town, and he's going to tell you more about that. It's not that the other is a bad idea; it's very crucial. It was just only half of an interesting whole. That's an old battle now. Now we're just trying to bring greater and better science to it all, to both sides.

ZIERLER: You've moved around so much in your career. What's the big explanation for that?

GAZZANIGA: Well, it always got better. That's a simple factor. You could say—a couple of them, there were personal things. I went through a divorce and that kind of thing. Now my wife Charlotte and I have been married for almost 40-plus years, and we moved a number of times too. Again, because the deal kept getting better and more exciting. I moved from Cornell Medical School up to Dartmouth Medical School because we had a baby in New York, and we were always up at Dartmouth because that's where many of the new split-brain patients lived. So, they said, "Why don't you just come?" and they offered me a job, so we just said, "Okay, we'll do that." We were very happy there, and then UC Davis came up—the chancellor himself came to our house in Norwich Vermont and said, "We want you to start this Center of Neuroscience." I had a good friend who thought I'd be good at it. So, they coaxed me into that. I did that. That was great fun. Great school. We were happy there. Then the Arts and Science part of Dartmouth said, "We want you now—we want to get cognitive neuroscience going within the College." Because the College and the Medical School were two quite different entities. I'm a Dartmouth grad, so I said, "Okay. Love that." So, we went back for that. Loved it, had a grand time. That brought me up to 65, 66 years old, and Santa Barbara says, "We want you to come out here." I had built a house there 40 years earlier, with my own two hands, and had kept the property. It's in Carpinteria overlooking the ocean. I was 65 and I said, "Let's go back." It would be a good way to do that. We did, and we've been here ever since. And we're not going anywhere!

ZIERLER: [laughs] Now that you've provided sort of the table of contents to everywhere you've worked, in our next conversation let's go all the way back to the beginning. We'll trace your upbringing, your family background, how you got interested in neuroscience. We'll take the story from there.

GAZZANIGA: All right! [End of Recording]

ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It is Monday, May 13th, 2024. It is my great pleasure to be back with Professor Michael Gazzaniga. Mike, as always, it's great to be with you. Thank you for joining again.

GAZZANIGA: Thank you for having me.

ZIERLER: Mike, we're going to go back all the way to the beginning today, after our first discussion, where we took a wonderful wide-angle look at all of your research, the things that are important to you. Let's go back and start with your parents. Tell me about them and where they're from.

GAZZANIGA: My mom and dad met on the steps of L.A. County Hospital on New Year's Day. He had gone to medical school in Chicago and left the day after his graduation. The story was that he wanted to get out of the cold and do his internship where it was warm, so he decided to take whichever train left Chicago first: Los Angeles or New Orleans. So that put my dad doing his internship in L.A. My mom was going in to work, she was the secretary to the Chief of Medicine, and my dad was on his way out to go to the 1933 Rose Bowl game. [laughs] The reason I know that is because I just looked it up to make sure I had the date right. Anyway, they met and married 3 ½ months later. My father was a physician and surgeon, and my mom was a homemaker. She took care of the five kids and got us all whipped into shape and they sent us on our way.

ZIERLER: Mike, are your parents from Southern California?

GAZZANIGA: My father was from Massachusetts. My mother was from Los Angeles. Yes, she was a third generation California girl. They temporarily, after he finished his internship, tried a stint back in Western Massachusetts, where a lot of his family was. He thought he'd practice medicine there. But they discovered on moving back that they missed the California sunshine (my mother's cousin sent her an orange blossom in February), and so they moved back after about nine months or so. My dad joined something called the Ross-Loos Medical Group, and it was the first prepaid medical plan in the United States, actually, and worked there all his life developing it. It became the plan that Kaiser Permanente copied. In Kaiser Permanente's history, they write about it. They took the model that these 12 guys had cooked up and took it to a far more extensive level. My parents had a good life, and they were very proud of what they did for medicine too.

ZIERLER: Now, Gazzaniga, is that an Italian name?

GAZZANIGA: Yes.

ZIERLER: Do you know what it means?

GAZZANIGA: [laughs] I know what it sounds like, and that we're not going to get into that.

ZIERLER: Okay. [laughs]

GAZZANIGA: [laughs]

ZIERLER: Now, what kind of medicine did your dad practice?

GAZZANIGA: He was a colorectal surgeon. How the medical group worked, much like they do today, they had offices throughout Southern California for GP and primary care. Then when there was a specific problem, they sent them down to the Los Angeles office, which is where he worked, where all the specialists worked. He was one of the surgical specialists. They sent all their patients at the time over to a major hospital, a private hospital in L.A. called Queen of Angels Hospital. They put together a mechanism that worked. They had their primary doctors feeding patients to the specialists, who then cared for them in a hospital nearby their office.

ZIERLER: Did your dad involve you in his career? Did you ever consider pursuing medicine yourself?

GAZZANIGA: Oh yeah, we were a very medically oriented family. My older brother did go on to get an MD. I was supposed to, and intervening in that was that summer at Caltech where I said, oh, wait a minute I think I like research better. I had to break the news to my dad that I thought I'd rather go to graduate school than medical school. He quipped at the time, he looked at me and he said, "Why would you want to be a PhD when you can hire one?" [laughs]

ZIERLER: [laughs]

GAZZANIGA: He was the total medical man talking. Then my Dad laughed and wished me good luck, and so forth.

ZIERLER: What neighborhood did you grow up in?

GAZZANIGA: The suburb of Los Angeles called Glendale, California. It was a typical middle-class area with a park across the street with tennis courts. I took the bus from a very young age to school, public school, all by myself. Got on, gave them a nickel and was then dropped off at school. It was a different time compared to all of today's protections, child care, and everything. No, no, the mother was at home, the father went off to work, and it was that kind of life.

ZIERLER: Did your family have religious affiliations, growing up?

GAZZANIGA: My dad was Catholic, and we were raised as Catholics—but my mother was not. She kept a lid on things. I remember once in a heartfelt time of my teenage years, I went to my mother and I said, "Mom I think I want to be a priest." She looked at me, and she says, "Uh-huh. Why don't you do something useful like be a doctor?" [laughs] So that put an end to that and I stayed in my premed career.

ZIERLER: You went to public schools, Glendale Public Schools, growing up?

GAZZANIGA: Absolutely, Glendale High School. Then I went to Dartmouth College, and the framework of that was set by one of my older brothers Al, who had gone—he was there at the time. I just thought that sounded like the greatest thing. My oldest brother, Don, went locally to University of Southern California. But I wanted to go away to college, and Alan was more my role model. He was a premed. I thought I was going to be a premed. Alan was also a major athlete, and he played football for Dartmouth and actually was an All-American second or third string—I forget—but named. It was something from an Ivy League college to have that.

But, at the time, if you did really well up through your junior year, Dartmouth Medical School let you skip your fourth year of college and roll right into the first year of Medical School. Alan was admitted after his third year and said, "I'm going to med school now." The football coach, Bob Blackman, went crazy. "What do you mean you're going to medical school? You've got to play here next year. I'm counting on you." [laughs] But he knew what he wanted—he wanted to be a physician—so he went off to medical school his senior year in college.

Zoology at Dartmouth

ZIERLER: Now, why Dartmouth? Were you looking at East Coast Ivy League schools in general?

GAZZANIGA: My dad was raised in Massachusetts, and he had gone to a small college in New Hampshire called Saint Anselm. He had always wanted to go to Dartmouth, and it just never materialized. He had been talking about this ideal school up the road from Saint Anselm, "Dartmouth, Dartmouth, Dartmouth." We just got interested in it, and my brother took the first plunge, and then it seemed great, by all reports. That's how it got going.

ZIERLER: What did you study at Dartmouth? What was your focus?

GAZZANIGA: Zoology. It was a typical class you would take in those days for premed. You took an astounding number of courses unrelated to anything. [laughs] It was filling up the calendar. In zoology, you had to take so many kinds of courses in classic biology. It was prior to the big splurge of going into molecular biology and the like. Certainly, that was going on, but it was not the intense curricula you see today. It was more broad-based education.

ZIERLER: Now, was Dartmouth coed in those years?

GAZZANIGA: Oh no. That came years later. Let's see, I think it was ‘74, so it was about 13–14 years later that it became coed. It was half its current size too, which is still small. But it was about, I think, a class was about 600 to 650 people. Now it's about 1,100 or so. It was a place that was all male during the week, and then on the weekend there were always—busloads of women coming up from Wellesley and Smith and Skidmore and others. There was a local junior college that would be frequented as well. You think back on it, I have memories of weekend trips to a school, and then coming back and saying, "Enough of that. We've got to get down to work here." Then come Wednesday, Thursday of the following week, you'd be planning [laughs] your next trip again. As anyone would expect, that was the flow at the time.

ZIERLER: Mike, did you have opportunity to do real lab work in a biology program at Dartmouth?

GAZZANIGA: I had the opportunity—a very important one—to work with an experimental psychologist by the name of William Smith, who studied visual perception, and he studied it through eye-tracking behavior. He had all kinds of new devices he was working on to accurately measure where someone was looking when looking at various kinds of stimuli. He had a lab up on the top of the psych building, McNutt Hall. Anyway, he let me join in his efforts as an assistant, as a young lab technician. I was there all the time. I thought it was great, because of that whole ‘catching on fire feeling' that a young scientist feels, making it up as you go along. You don't know what you're doing. Everybody else is just saying, "Come on, let's try this, let's try that." There were very few off-the-shelf devices you could slap on somebody and it did all the work for you. You had to devise stuff on your own, and he gave me the confidence to do that. We built some things and started some work. He and I remained good friends. In fact, later on when I was at Caltech, he wanted to come out and spend his sabbatical. Roger didn't really know who he was, so I introduced them, and they got along quite well, and he came out for a year.

ZIERLER: Mike, would you say this experience was the formative turning point in you deciding to go to graduate school and not medical school?

GAZZANIGA: I think the formative one was that summer at Caltech. I don't know if it was because I had no expectancy what it would be like and, therefore, it was just like Fourth of July! Everybody was working, thinking of new stuff, and letting you do it. I've said this before, the whole attitude was, "Just do it. Try it. Go ahead. What's stopping you? It's up to you. Get going." And everybody was there to help you out. It was just a remarkable environment in every way.

ZIERLER: Now, growing up in Glendale, being essentially next door to Caltech, were you aware of Caltech? Had you heard the names of Richard Feynman and Linus Pauling?

GAZZANIGA: No. [laughs]

ZIERLER: Amazing. That's amazing.

GAZZANIGA: I was a teenager, playing football, and doing things that you do to get into college. You'd do homework, and then you'd play football, and then you'd have a girlfriend, and you'd drive your coupe around town. It wasn't that I was not interested in scientific things, but it never connected as a career goal. I suppose, if you thought about it, Caltech was held up as this place that some people go to. It's not, oh yeah, then you just go to Caltech. It was known as a special place, but I never thought about it. I only thought about it upon arriving at Dartmouth.

Then the studies became serious, and I discovered the work of Sperry on nerve regeneration, and he was at Caltech. I had a girlfriend, who lived next door to Caltech in the summer. I thought, well, if I could get a job at Caltech, I'd have an excuse to drive over to see her in San Marino, which was right there by Caltech—and those kind of silly little stories. But who knows what, you know, who knows why you do what you do?

ZIERLER: Mike, how did you first come across Roger Sperry's research?

GAZZANIGA: It was part of a course reading assignment at Dartmouth. I forget which course it was. He wrote an article around that time on The growth of nerve circuits. I think that was the title of it. Roger was, if you go into his history, an English major and, boy, could he write. He was a great scientist too, but he could craft a story beautifully. He wrote this paper, The growth of nerve circuits, about an engrossing problem. How do the parts of the brain hook up with each other? How do neurons get to where they're going to go? How does that work?

Fundamental questions. He did an incredible series of experiments, and this paper reviewed what he had done up to that point. You couldn't help but be totally engaged. Then I noticed he was at Caltech and I wrote to him and said, "How about a job?"

ZIERLER: Now, when you got to Caltech, did you know you wanted to study with Roger? Was that sort of completed even before you arrived in Pasadena?

GAZZANIGA: Oh yeah, he took me into his lab. He said, "Sure! You can come work for me." This is a typical thing. Students write professors. The professor agrees. At this point in the process of science development, it's all informal—at least it used to be. It was just between you and the professor. If they had a desk, and they had some intern monies or something, they paid you a little bit, and you're in business. That can still happen today, those kinds of informal arrangements. But now there are undergraduate programs and all the rest. I wrote in a book, trying to speak to young students. I said, you know, my line was ‘write the letter.' You find somebody that you're interested in? Write them a letter. See what happens—because that's how it got going with me. Unfortunately, that suggestion has stuck [laughs], and now you get letters that you just can't possibly fulfill because there's too many kids that want it. But from a professor's point of view, if it's a genuine letter, it's a great connection because the student then shows some real interest in your topic. You don't have to take them and bring them along on your topic and see if they're interested. They're interested in it because they wrote you, and they know that somehow that relates to their goals, and that's always a big help.

ZIERLER: Mike, was Roger an island at Caltech? Were there other faculty engaged in what was called psychobiology?

GAZZANIGA: He was certainly the most psychologically involved. If there was going to be—using the terms learning and memory and cognition or psychology itself, he would be the contact point at the time. There were other people involved in the nervous system: Wiersma, Van Harreveld, and others you can think of. But they were more basic cellular physiologists trying to figure out cell behavior, cell to simple behavior in animals. They wouldn't be called psychobiologists. But when Sperry arrived at Caltech, he started off his lab, in addition to his ongoing nerve growth work, he brought in cats and monkeys, to work on them in the early days of animal split-brain research. He and Ron Meyers really got that going at Caltech as well.

Roger Sperry and Human Subjects

ZIERLER: Now, when you got to Caltech, was he already involved in what would be called split-brain research?

GAZZANIGA: Roger was working with animals. The human stuff started in ‘61 with me and then the first patient coming along. That was proposed by Dr. Joe Bogen, a post doc at the time, working for Anthonie Van Harreveld, whose office was right next door to Sperry's. That patient came over from a local hospital. The thought was that he should undergo split-brain surgery, and who was going to test him, and all that sort of stuff. That's just exactly when I was arriving, so I was assigned—I got the assignment, as it were.

ZIERLER: Were there any prevailing theories about cerebral dominance or just the anatomy of the brain that provided an intellectual framework for the experimental research?

GAZZANIGA: Sure. It's a long history, of course. The animal work set it up simply. They, at that point, had known you trained one-half of the cat brain on something, and the other half brain didn't know about it. The same was true for the monkey. But it was just unimaginable that it was true in a human. What do you mean? My left hand doesn't know what my right hand is doing? Come on! That's sci-fi stuff. Then the existing literature at that point, human literature from neurology, confirmed that there were no effects. The notion that it would be true in humans was not commonly felt. In fact, it was assumed it wouldn't be true, for reasons people didn't quite understand. That's where it sat. I think I mentioned this. After I spent my junior summer at Caltech and got interested, I realized that there were patients who had had a form of split-brain surgery at the University of Rochester in Rochester, New York.

To make a long story short, during my senior year at Dartmouth, I asked Roger, "Why don't I go down there during my spring break and see if I can do some tests and get some indication if these patients might have some of these effects." I got permission from the neurosurgeon in Rochester to come down and try and test them. We were going to see—with lateralized testing, maybe we could find something. Sperry and I corresponded, and we came up with a bunch of tests. I got a little grant from the Dartmouth Hitchcock Foundation to rent a car, and I drove down there.

When I got there, the resident neurosurgeon at the time, Frank Smith, had changed his mind about whether this undergraduate from Dartmouth should be looking through medical records. [laughs] He said, "This probably isn't a good idea" sent me home. That was the end of that episode and I never was able to test them. But it was just a few months later that I started at Caltech. It was natural for Sperry to say, "Well, you test this guy that's coming in, because you've done these tests before or worked up these tests." That's how it started. As I say, the context wasn't that there's a gold mine in that room, and you just mine it. The context was, you're not going to find anything, because that's what the literature says. It was all due to the fact that the prior investigators hadn't properly lateralized the tests to one side of the brain or the other; they just were soft about that. I was better prepared, having studied eye-tracking with William Smith. When we got it all worked out on how to test the first patient WJ, before his surgery, he turned out to be just like you and me. He didn't show anything. His two hemispheres were hooked up, and we didn't see any lateralization effects. Then after he had his surgery, as soon as we were able to test him properly, all the effects started pouring out of him.

ZIERLER: We'll get more into that. But, just for background, I wonder if you can talk a little bit about Sperry's research operation. How many graduate students did he have?

GAZZANIGA: He didn't have that many grad students. There was Charles Hamilton and me there at the time. He had a lot of postdocs, and I think it was more of a postdoc-driven lab. Colwyn Trevarthen, who had been a graduate student of Sperry's was a very forceful, important person, Mitch Glickstein was another very important postdoc. Then Ted Voneida, who may have been an instructor or a little higher on the food chain there, he was there doing a lot of cat work. Then there were people—Harbans Arora, who worked on the nerve growth. There were six or seven people. Other people, visitors came through—Nico Spinelli. I could go down a list of people that fed through the lab working on all kinds of problems. Roger kept his nerve growth work going. It was central to developmental neurobiology. The split-brain work on animals was very active. The new project on human split-brain work kind of coming in on top of that.

ZIERLER: What was the instrumentation? What was the experimental apparatus?

GAZZANIGA: It was pretty primitive. You had to project visual information on something, and so I built a screen and put this special material on it that you could back-project on it. Imagine a screen, and a slide projector projecting on image on it from behind, and the patient was on the other side looking at it. You could, with a slide projector, project images. If you're on the other side of it, you would see the images, focused on this screen. Then you would tell the patient to look at a particular point on the screen. If they did that—the way your brain's hooked up—everything to the left of the fixation point went to the right-half brain, and everything to the right of the fixation point went to the left-half of the brain —and that was only true if you quick-flashed it, because if you allowed the patients to move their eyes, then they could mix the information all up, and you wouldn't have a lateralized picture. I remember one of the first devices. I held this screen, balanced it on a rope over a water pipe in one of those Alles labs. We got it situated, and the patient here, and then I was there, and we just got going. We had to quick-flash using a camera shutter because we weren't using computers and all the rest. This was way prior to that. We just had these—it's like a camera shutter that you have in the old days to take a picture. You could quick-flash it for 100 milliseconds and that would make sure that the person couldn't cheat. The image that was projected would only go to the part of the brain you intended it to go to. That was the trick that really broke open the dam, as it were, and let everybody see that there are ways of showing these disconnection effects.

ZIERLER: Mike, were computers in use at all? Were they available for this kind of research?

GAZZANIGA: Not really. That came later. It was all hand done. You're making stimuli. Everything was a pain in the neck. You had to get the artwork done. You had to take photographs. You had to translate them to slides. There was a whole thing. It wasn't, open your laptop, pull up the program, put in the picture, and we're ready to go a minute later, no. Don't we wish? I was simultaneously also doing monkey primate research too, split-brain monkey. We had to build these circuit boards that allowed stimuli to be presented. We had all kinds of stuff going on. Another thing I should point out, there were two or three support staff, one in Sperry's lab, Lois MacBird, who managed all the animal work and the animal surgeries and all that that goes into that huge effort. Then there was a shop guy, Reggie. These people knew what they were doing, and they committed their lives to make the life of the scientists a little bit easier. They had all the skills of how to build stuff and so forth. You would interact with them daily, and they would help you. Such an important part of a large scientific effort is the supporting staff.

ZIERLER: Was the thrust of the animal research that ultimately this would be applied in a clinical environment, that there would be human patients for experimentation?

GAZZANIGA: No. It was pure human curiosity. Just ‘what is this?'

ZIERLER: Basically, fundamental research, basic science?

GAZZANIGA: Yeah.

ZIERLER: No one was talking about what we would now call translational research or start- up kind of interests?

GAZZANIGA: No.

ZIERLER: Mike, tell me about Roger Sperry as a person. What was he like?

GAZZANIGA: I adored the guy. He was a quiet man. He wasn't—how to put it? He wasn't a bullshitter. He had conversations that were always calm. I talked to him during my graduate years and postdoc years there. I was there a total of five years. We talked all the time. It wouldn't be overstating to say we would talk for one or two hours every day. It was because I was working like crazy, and I would always present the data to him, and we would talk about it and go through it. Then as we got into the human testing, he started spending more time on it and would come in for the testing when I brought the patients into town, and so forth. We had a wonderful relationship. In fact, Jim Bonner, who was a professor at the time—a protein chemist, if I remember that correctly—had said that maybe we should hire Gazzaniga so Roger has somebody to talk to. He wasn't "aloof." That isn't the word; just private, I guess. But I had a wonderful relationship with him during those years, and we talked all the time. He had parties. A funny little aspect of him was he would throw these parties up at his home, and the whole lab would go, and he loved it. Then there was a part of his life I don't know anything about: He and his wife were square dancers, and they belonged to some local club there in Pasadena. I remember him saying that they went out square dancing last night. I went, "Square dancing?

What are you talking about?" I was not into square dancing. He had his own very private social life.

ZIERLER: What was his style like as a mentor? Would he direct your work, or you had room to do what you wanted to do?

GAZZANIGA: Oh, absolutely the latter, he was really good at letting you do what you wanted to do. Of course, retrospectively, you don't know actually who was doing what, because there would be these conversations. But he was all for, I mean, you would propose something, you'd be doing something, and then as you're telling him all about it, he's making suggestions along the way. If you look at the end product, it's obviously a collaborative effort, and so you just leave it at that. There are some labs you go to, and you walk in, and there's an assignment board there. The professor wants X, Y, and Z done. Which one are you going to do? Kind of graduate training, right? Total opposite of that, total, complete opposite. You walked in and, after a while, you started having your own ideas. If they were reasonable, if they were in the context, and even if they were on the fringe, try it. One of his lines was, "Never read up about an idea. Just go try it. Then go read about it." Because if you read up beforehand, it could bias you away from something. There's a dogma that's established by the other guy, and he wants you to believe it, so that's all you see when you're doing your thing. All that kind of wisdom came from Roger. But you went to him with proposals. He was not prone to directing you to do things. I mean, I say that in light of the fact there's got to be—there was always a two-way street going on. It wasn't not that. But it wasn't the kind of lab where you got an assignment. Not at all, and that's what made it great. That's why people loved it.

ZIERLER: What were his interactions with other faculty at Caltech? For example, I'm thinking when Seymour Benzer got interested in the genetic basis of behavior. Would they engage on those kinds of topics?

GAZZANIGA: I don't know. I don't know. There weren't situations where you would have Sperry, Seymour and, say, me kicking it around. No, that didn't happen. But Seymour was great. He was very open, too, another open guy. He would kick around with the grad students and postdocs what he was up to his new fly work. We would comment on it, for sure. It was fascinating. He was right next door. I don't know if it's still this way, but grad students, postdocs, and visiting professors are all right there. They're not situated psychologically or geographically apart. You interacted all the time. I never had the sense of political issues while at Caltech. It just wasn't there. If they were going on, they were kept from us. We weren't part of it.

Visual Coordination in the Brain

ZIERLER: Mike, tell me about developing your dissertation research. What did you work on?

GAZZANIGA: A lot of it was the split-brain patient, and a lot of it was issues in what's called visual-motor coordination and mechanisms, and I did that in monkeys. It was centered on primates and humans. You can think of it in terms of visual-motor control, visual perception interactions, language specialization in the hemispheres. Those were all things I did. My thesis was five or six chapters, if I remember correctly. They were basically five or six papers that had been coming out during my graduate training. It wasn't a typical thesis where you take this one point, and drive it into the ground. There were all these things you could do because you could do the beginning, middle, and end in each chapter. You could test this or that idea or question on the patient with a callosotomy, and you got an answer in that chapter on whatever question you were asking, or you got findings before you got the answer. Those are long stories. It went quickly. I finished my PhD work in three years, and then they actually awarded the degree the following summer, so it looks like four. But it came the previous October, so it was just right afterwords that I switched to being a postdoc right there and also got a raise. That was great.

ZIERLER: Now, the title of your thesis, Some Effects of Cerebral Commissurotomy on Monkey and Man. Let's start with the word "commissurotomy." What does that mean?

GAZZANIGA: The connections between the two brains are called the commissures. There's the great cerebral commissure, the corpus callosum. That's the big one. Then there are smaller ones: the anterior commissure; the habenular commissure; the hippocampal commissure…there's a whole bunch of little commissures. The main one that the whole story's about is the great cerebral commissure, the corpus callosum, and, in the Caltech series of human patients, also the anterior commissure. Those were the structures that were sectioned that produced the disconnection effects. Were there any differences between monkeys and humans? Big question. Were there differences between the cats, monkeys, and humans? The answer was, yeah, there were differences. If you left the anterior commissure intact in a monkey, they didn't show any visual split-brain effects. If you left it intact in a human, it didn't matter. It showed all those split-brain effects. There were different distributions where those commissures innervated and transmitted information in the two species. That fact holds up to today.

Then we were trying to figure out the mechanism of how does one brain, say, the left hemisphere control the right hand? Well, that's easy. All the sensory motor information is all in the same half-brain. But how did the left hemisphere control the left hand? Because the part of the brain that has all the controlling stuff for that hand is in the other hemisphere, and you've disconnected it. How does that work? Just a simple question like that.

Well, that opened up a whole bunch of work on—and the early work on what's called cross- cueing, how one hemisphere of the brain can cue the disconnected other one outside of internal mechanisms by posturing in certain ways. Imagine yourself strapped side by side to somebody, two heads and everything, but you're strapped to them, and they move their hand somewhere. You both can pretty well figure out where the hand has gone because your body is being carried and twisted along with the other, which means your brain is getting all that kind of reafferent information. It kind of knows something about where the hand is in space. It's not completely devoid of information. That became the monkey work, and we took a lot of that thinking into the human work to show how these two separated minds, as it were, coordinated with themselves and made it look like they're really a unified system when, in fact, they weren't. A modern little metaphor I use is—have you ever tango danced?

ZIERLER: Sure!

GAZZANIGA: That whole thing of cuing your partner and them cuing you on how to dance and then where to put your next step. Just imagine that's what's going on with two half-brains. They were separated. They've quickly learned how to tango dance to get the job done and to get you to a particular point in space.

ZIERLER: Mike, now thinking about monkey and man, obviously you are interested in human subjects, but absent the experiment, what did you actually have to say about the human brain?

GAZZANIGA: What did we have to say about it?

ZIERLER: Yeah!

GAZZANIGA: In what sense?

ZIERLER: If you're not experimenting on humans for the dissertation research, how do you know what to write about? How do you know what the experiments look like? What are the findings?

GAZZANIGA: By experimenting. Not surprisingly, one of the first findings was that there's a dominant hemisphere that speaks and talks to you, and there's a nondominant hemisphere that doesn't. You ask, "What are the other psychological functions that nondominant hemisphere can do?" Then you have to test all kinds of things. What if you give it a problem to solve? Can it solve a problem? Does it have the cognitive apparatus to solve a problem? Because we know the left hemisphere can solve this little problem, whatever it is, can the right hemisphere solve that problem? That would require designing particular tests, lateralizing them, looking for a nonverbal response to seek your answer, and compare if these two half-brains are really coequal in all the domains of cognition that we normally think of. That became a huge challenge over the years to figure out how good was the right hemisphere. Was it different? Could it solve different things, not the same things as the left. What was the evidence for that? A lot of people worked long and hard working out all those details. Then through time, of course, it's a moving target. The brains are changing. These patients lived 20, 30 years post-surgery. If you were testing them carefully along the way, you would see changes where, all of a sudden, it looks like their right hemisphere, which immediately after surgery had no speech at all, and then over time, it looked like they began to speak. What's that all about? Can you get markers of understanding in the development of speech? We shorthand this thing: left, right, split-brain.

Bingo! No, no, no! There's 50 years and hundreds of papers of very carefully designed experiments, getting at all these different aspects of the issue. What is lateralized? What isn't lateralized? Does it change? Is there plasticity? What are the cueing mechanisms? How can we use this data to figure out how the brain communicates and underlies our cognitive unity? That's what it's all about. It's still ongoing with a new series, and we're trying to figure some of that stuff out.

ZIERLER: Mike, what did the actual experiment look like for your thesis?

GAZZANIGA: There isn't an actual experiment for the thesis. There are many experiments. A simple one could be, in the early days, what kind of visual-matching capacity does each hemisphere have? If I show you a triangle in your left visual field, which goes to your right hemisphere, the split-brain patient would say they didn't see anything. That'd be the standard response. That's where you'd start. But then with the left hand, could they go out and pick a stimulus that matched the picture you in fact showed them from a group of pictures? Yes, they could. Then you start making those subtler and subtler in different dimensions to the stimulus to see how good it was at it. It turned out to be very good at it—in some cases, superior to the left hemisphere. Then maybe, are there lateral specializations in the right hemisphere that the left hemisphere doesn't have? Oh yeah, it looks like there are a few. That's the work that took all kinds of time to work out, and a lot of people worked on that. It got going when I was there, and then Jerre Levy came in later with Colwyn Trevarthen and Roger, and they did more studies on that kind of problem. Bob Nebes came in and did more. That was all going on after I had moved first to UC Santa Barbara and then east to NYU, and we were beginning to study the East Coast series of patients on different kinds of problems. It was a very busy time.

ZIERLER: How closely involved was Sperry in this work? Would you meet with him weekly? Was it less frequent than that?

GAZZANIGA: There weren't weekly meetings. It was just a continuing conversation. As I said, at the time, I met him every day, and we'd talk. It wasn't you'd get to see Roger at Tuesday between 2:30 and 3:15, no.

ZIERLER: He was around?

GAZZANIGA: He was around, and you knew because his door was a little bit open. That meant it was free game to knock on the door and see if you could come in.

ZIERLER: Now, could you reverse engineer? Obviously no one knew where this research was headed. But can you reverse engineer his Nobel Prize in ‘81 for what he was doing when you were a grad student?

GAZZANIGA: The Nobel Prize Award cited the human split-brain work. That was our work, there's no question about that. Yet anybody who had followed his career and knew his work generally, I think most people would've said, well, he could have gotten it for two or three other things too. That's the remarkable thing. In particular, his nerve specificity work was unbelievable. I think, oh, isn't it interesting they just picked that one, because they could have mentioned the other work. But his co-recipients were in those domains that he could have gotten a prize, so maybe they felt it was redundant. Why not give it to him for something else? One of the really beneficial effects, of course, was to telegraph to the world that trying to do experimental work on humans was noteworthy, was important, and it gave a great boost to the general areas of psychobiology, whatever you want to call it now, cognitive neuroscience, physiological psychology. That was good stuff.

ZIERLER: Now, I guess what I'm asking about, reverse engineering, was anybody talking during your time at Caltech that this work was Nobel Prizeworthy, that there was a buzz about this research?

GAZZANIGA: I don't know. I mean, I left. That was 20 years after I left, or 15 years or so after I left. When you're a hardworking grad student, you didn't talk that way. Well, anybody that does talk that way, you kind of get out. [laughs]

ZIERLER: Get out of here! [laughs]

GAZZANIGA: We're just trying to get this thing done.

ZIERLER: Mike, when did your experiments reach a level of finality or completeness, where you felt ready to defend?

GAZZANIGA: That's a good question. I don't know. There were a lot of, I mean, Caltech was really a family, and it was time for this guy to move on because there's something else we want to get done here. I don't know how that worked, to tell you the truth. For example, all of a sudden, I was asked if I would—during my early graduate years—would I mind running the student center there as a sideline? "We'll give you a secretary to do it, and we'll pay you." I was married and looking for income and so forth. "You've got your fellowship. You'll have extra money. We'll pay you extra." I said, "What's involved?" They said, "Not much." I don't know, once a week, I would go there, and talk to the secretary for 20 minutes. I have absolutely no memory of what that was about. But I ran it, and apparently did a good job. Those sort of things are little pieces that just kept everybody's ship afloat and going on. Then it was time to maybe get a raise. How do you get a raise? You can wrap up. You've been working here for three years, and you got all this work done and all these papers out. Why don't you just staple them together, and let's have the final PhD test? I mean, it was that kind of informality.

I'd gone through all the tests. I think I mentioned this before. There were three or four hallmark tests you had to take from outside professors. I passed all those, and so I was ready. The other thing at Caltech—at least it was true for me—when you came in as a grad student, you went to work, day one. You went into the lab. The courses were nuisances you had to do. "Well, you've got to take this. We're running an institution here." But the feel of it was, contribute to the—get a part of the research, get the context of the research, and learn as you go. Of course, you learned. Where you did your real learning was what you had to learn to do for whatever it is you wanted to do. That was when you say, what does somebody's body of work look like after three or four years? There's a lot. Currently, the graduate student training is the first couple years or classwork plus this and that. Then you gradually get into a lab. Maybe by the end of your fourth or fifth year, you've got something to show somebody. That's not how it was as I remember it.

ZIERLER: Mike, were there other Caltech faculty that you worked with closely or you would've even considered mentors?

GAZZANIGA: Certainly friendly with a lot of them. Norm Davidson. These people were far afield from what we did. Anthonie Van Harreveld, right next door, I talked to him several times. Felix Strumwasser, again. But they were just generally supportive. It was close with Sperry and his postdocs, who were very involved in helping train the grad students. I mentioned Mitch Glickstein, Colwyn Trevarthen and Ted Voneida. These people we were talking to all the time as well. They were a very important part of it.

ZIERLER: Do you remember who else was on your thesis committee?

GAZZANIGA: I have no idea who was on it. My minor, of course, was Ray Owen. I minored in immunology, so he was on the committee. It was Ray and Roger. I think it was Felix Strumwasser. I don't know.

ZIERLER: Anything memorable from the oral defense? Any interesting conversations?

GAZZANIGA: No.

The Pisa Connection

ZIERLER: Now, did you know you were going to stay at Caltech for a postdoc? Were you looking elsewhere?

GAZZANIGA: Yeah, I knew I was going to stay at Caltech for a couple of years. Then the plan—I don't know if I mentioned this. We had a visitor from Italy, Giovanni Berlucchi. He was an MD, and he was out of the very famous laboratory of Giuseppe Moruzzi. who had been at UCLA with Horace Magoun and did a lot of world-class sleep research. Berlucchi was over to spend time with Sperry, a sabbatical year. He and I became very close friends. Then the plan was, after Caltech, I'd have a fellowship to go to Pisa, Italy, and work in the Institute of Physiology where Moruzzi was head and Berlucchi was returning to. So we did that, we went to Pisa for three months. Sperry came and visited. But I was antsy to get back. I had accepted a job at UC Santa Barbara, and I was antsy to start. I found out I didn't have the patience for neurophysiology. It requires sitting for hours with an electrode in some cat cell, looking for something that makes the cell discharge. It's just not my style. I said, come on, I want to get back to what I do, more whole-body behavior and so forth. I left early and came back to Santa Barbara, started my job, six months early I think, whatever it was, and got my lab going. Then after three years I left Santa Barbara and went back east. But my first job was just right up the road from Caltech at UC Santa Barbara.

ZIERLER: Now, the postdoc, was that more or less tying up loose ends with the thesis or was this really an opportunity for those two years to expand the research, take on new projects?

GAZZANIGA: The idea behind the postdoc in Pisa was very bold and, in retrospect, too simplistic. We knew that visual information transferred from one half brain to the other, and we knew where it transferred. It transferred through the corpus callosum. Our [laughs] oversimplistic idea was we were going to put an electrode in the corpus callosum, flash information to one brain, and figure out the code that transferred that information over to the other brain; some very simplistic notion like that. We applied for a grant and got money to do it, and that was the work, and it worked fine. I left it after a while, and Berlucchi and Giacomo Rizzolatti, who was also there at the time, finished the work. They found out a whole story about the nature of the visual midline and what transferred. It was a very basic neurophysiology story. The whole rich three months' experience was something. They had to build a special lab in the garden of the Istituto di Fisiologia in Pisa. That meant they had to go down to an auto body shop somewhere in Pisa and get them to build these huge half-domes, which would be the visual display the cat would be looking at, right?... this big thing. [laughs] In order to get it into the Istituto di Fisiologia, because of the narrow 16th century gates, they had to first cut the dome in half and then re-bolt it together [laughs] on the other side. All these stories were going on. It was just, I mean, Fellini could've made a comic movie out of it all. But they got it done, and they did the first work on it right there, two fantastic neurophysiologists, getting the work done. Early days, as they say. Both of them are great scientists and people.

ZIERLER: Tell me about your time in Italy. What was it like?

GAZZANIGA: Italy is the country. They ought to just turn it into a park for the world so that—

ZIERLER: [laughs]

GAZZANIGA: —we always have it. It was great. We learned all kinds of things. We did side trips, traveling, and all the rest of it. For me, it was a real serious exposure to neurophysiology with these guys, just what's involved. It's a tough trade. It's trying to make sense out of what first looks just like random correlations and bringing it into a causal model.

They were very clever. All of them were very clever, very smart, very intense.

ZIERLER: Do you have a sense of the history, why Pisa was a center for neurophysiology?

GAZZANIGA: It was Italy's, I think, major lab at the time. Giuseppe Moruzzi was a very senior scientist at that time and very involved and caring. But it was Berlucchi and Rizzolatti that were the new blood—they were going to be the next generation, and they had been picked. The Italian academic system works in different ways, but they were clearly chosen to come in—as they should have been. They're fantastic people. They stayed there for a while, and then they went off to their famous careers as well. Berlucchi went off to the University of Verona and Rizzolatti to the University of Parma.

ZIERLER: Did you go on the job market from Italy, or you had the job at Santa Barbara wrapped up already?

GAZZANIGA: Yeah, I already had it. Again, different times, different days. I remember in the old days, there were no phones in the labs of Caltech postdocs and grad students. There was a hall phone. If anybody called anybody, the hall phone rang. Anybody who happened to be walking by answered it. They would say, "Is Colwyn there, or is Mike there, or is Mitch there?" Then you would have to find the person, and say, "There's a phone call for you."

ZIERLER: [laughs]

GAZZANIGA: That was supposed to cut down, I suppose, on people sitting at their desk, making phone calls or something. [laughs] I don't know what it was. But, anyway, I just remember vividly getting a call on that phone, and it was the chairman of psychology at UCSB saying, "Hey, listen, how would you like a job?" It was just cowboy stuff. It was prior to all the layers and layers and layers of regulations—just a different time.

ZIERLER: The program—the department is psychology. Were there neurobiology or psychobiology programs to apply to at that point?

GAZZANIGA: There may have been. They would've been called psychobiology or, in psychology, just to take an example, psychology is one of these suitcase words. It covers all kinds of stuff: social, personality, organizational. Physiological was a big term. There might be an ad for a physiological psychologist in the psychology department. Now it would be neuroscience, sometimes in the psychology department. But now a lot of people are changing their names to psychological and brain science departments from psychology—some are; some are not. All these things are going on as people try to hone in on what it is they're doing, and what name would best capture it. But it's a big debate. There are psychological levels of analysis, and who cares how the brain does it physically? There's still this psychological level of analysis that we all know about, and we can see causal relations between this and that. You could be interested in all the biology of it, but you don't have to be. You can do your work and do it well by just staying at the layer that you're thinking about. Those conversations continue today in these departments.

ZIERLER: Mike, tell me about the psychology department at UC Santa Barbara. Was it well established? Was it in growth mode by the time you joined?

GAZZANIGA: It had some very well-known psychologists at the time, totally unbeknownst to me because I didn't know about general psychology. I came up with Linus Pauling down the hall, and Max Delbrück, literally. I mean, psychology, what's that? Sperry said, "No. Psychology is good. Those guys think a lot, and it's a good environment." There was the guy who hired me and his wife—Howard and Tracy Kendler, who were big parts of what was called SR psychology, stimulus-response psych, which was the behaviorism form of psychology. Then there was also the ingenious, absolutely brilliant David Premack, who's the guy that first seriously trained a chimp on some meta-language systems. He raised the chimp at the department. In fact, my lab was next to Sarah the chimp's lab. Sarah the chimp was very matter-of-factly taken out on the front lawn of the psych department here every day for exercise by her trainer. That whole, I mean, that was crazy to me that they were teaching chimps language. That was so mind-boggling from coming out of a straight psychobiology training.

Then there were other people. There was a very talented group of people. UC gets all kinds of kudos, in my eye. They pick good people. There are very strenuous reviews, and it's just got a bigger canvas it has to play to because of the educational need. But I would say they all get A's. During my first stint at Santa Barbara, I was trying to recruit Roger to come up and be a professor.

ZIERLER: Oh wow.

GAZZANIGA: He came up for a couple of visits, and I showed him around, and he was thinking about things, how he would do things. Then somehow, all of a sudden, no, we're not going to do that.

ZIERLER: But he considered it?

GAZZANIGA: Oh yeah. It was very active. He met with people in the administration. I thought the hook, quite frankly, was the natural beauty of Santa Barbara and the ocean and that frame. It was very underdeveloped at that time versus the sort of luxurious setting of Pasadena. He was very much a naturalist, so I thought that might have a special appeal—but I guess not.

ZIERLER: Tell me about setting up your lab as a young assistant professor. What was most important to you?

GAZZANIGA: That's a good question. There was the realization that you had to do it. It was all on you. You don't have a staff to do it. You didn't have that easy knowledge and skills that were available at Caltech from—I had mentioned earlier—Reggie the shop guy and Lois, who did all the surgeries and aseptic things. I had to set all that up because I was doing primarily primate work. I had to set up sterile surgeries. I had to set up and build new training boxes. I had to do all that stuff. I was doing it alone until I hired a young guy who had graduated and had some physical skills, carpentry skills. He came on and helped me tremendously with the building of apparatus. Then there was an electronics guy that helped me build new systems to train monkeys and do things from a more computer-based way in terms of presenting stimuli, and recording their responses, and all that. And teaching. Bingo, slam, you're teaching now, buddy. That's part of the show here. I can remember that just being a shocker to the system: You have to put 30 coherent lectures together while you're trying to do all this other stuff, when you had been 100% research before. I now hear this lament from every new assistant professor we hire. If they've come out of a really first-rate research lab, their last years as a student or postdoc were all research. Then all of a sudden, bingo, 30 lectures. Either 60 kids or 600; it doesn't matter.

One of my courses I was assigned was the Psychology 1 course, which had 800 kids in it in Campbell Hall.

ZIERLER: Wow.

GAZZANIGA: You're not ready for that. I remember little tricks. If you lose 10 percent of 800 kids, that's 80 less kids making noise in the class.

ZIERLER: Yeah. [laughs]

GAZZANIGA: Coughing, sneezing, getting up, you know, it's not good. How do you manage this just so you could sustain a thought, and keep it going, and everything? I stumbled upon this one way where, during one lecture, somebody got up—they were sitting close to the front row—and theatrically walked down the middle aisle out. I stopped lecturing, and everybody got still—and then they all cast their eyes on this person walking up the aisle. So, 799 kids are now looking at that person. After that event, nobody walked out anymore. No one wanted that feeling of being the distraction. You had to learn all kinds of mass teaching techniques. That was an exaggerated one. But the classes could be—they were always much bigger than Caltech, you know, 100–120, sometimes 60. You just had to learn things. Then what you considered a lecture actually was about four lectures, because you're really supposed to spell it out. These kids come in, and they don't know anything about what you're talking about and are only vaguely interested in it. You would go in, drop into jargon, and do stuff. Then the hardest one for me to get over was the old saying, you don't know anything till you have to teach it—and, boy, is that true. I would be talking about something that I'd read 100 times and thought I had an understanding of and then tried to spell it out step-by-step. In the middle of a lecture, sometimes I'd realize, I don't believe this work, it doesn't make sense. [laughs] Then there's this second person talking to me in my head at the same time asking, why am I up here lecturing? [laughs] All that goes into the first year or two of teaching. It's time consuming. It's hard work. You know all the time, however, because everybody tells you this, the only thing that counts is your research, so don't lose track of that. They may be filling your day up with this teaching, but they don't really care how you do it—that's changed a lot. They do care now, and you've also got to get the research out. That's still true. At research universities you're primarily evaluated on your research.

ZIERLER: Mike, as a faculty member with your own lab, how did your research branch out? What new things did you take on at Santa Barbara?

GAZZANIGA: I think I would put it this way. My own research was sufficiently rich, to me, and fulfilling, and busy that I was happy pursuing it, and I thought I was doing good things and all that. I became interested in social political issues as well. I can remember it was during that time when Robert Kennedy was assassinated, and I was just horrified by that. I organized and held a meeting here in Santa Barbara and brought in some famous psychologists and biologists. I was just thinking about this. I had Leon Festinger and Dave Premack, who was local, Paul Meehl and Stan Schachter came in, and also Robert Sinsheimer, who had just become Caltech's chair of Biology. He was always very interested in social questions too. I knew him slightly; not well. Anyway, we all came to town and tried to figure out what all this meant for the time. Those things really interested me, and it set the stage for things that I've done all my life, that is, always have extra intellectual groups getting together and thinking about big issues. It brought color to the work. Once when I was at Caltech, the comedian Steve Allen wanted to come over and bring his family one Sunday to visit. Sperry always handed those things off to me and others.

He came through and had a wonderful visit, wonderful family. Steve Allen was also very enthusiastic and supportive. He says, "This is fascinating. How much of this research is fascinating?" or something like that. I said, "About 10 percent; the rest of it's just drudgery." It's just true, I mean, it's true for all of us. You've got to do the background, you've got to do the thing, you've got to build it, all this stuff that's got nothing to do with the question you're trying to answer. Everybody who goes into science realizes there's a lot of drudgery to it, too, a lot of repetition. It's true, if you think about it, I guess, it's true in all professions. But on the outside, it always looks like you're constantly discovering the secrets of nature. No! [laughs] Mother Nature's really good at keeping secrets.

The Bisected Brain

ZIERLER: [laughs] Mike, tell me, when did you get the idea for writing The Bisected Brain, and what audiences were you hoping to reach?

GAZZANIGA: I was invited to write that book by Professor Arnie Towe at the University of Washington. He served as editor of a series of books. He wrote to me out of the blue, and said, "Would you like to do this?" I said, "Yeah, sure!" I was at Santa Barbara at the time, and I put it together, and the book is just a reflection of the early days of split-brain work. I think it came out—when did it?

ZIERLER: '70, I think.

GAZZANIGA: Yeah. It became a recounting of my early experience and I also tried to put together a few ideas for the future.

ZIERLER: What were those ideas? What did you want to help shape in terms of future research?

GAZZANIGA: We were beginning to think about how we might be able to apply some of the things we were doing in patients with aphasia. I had met, as I told you, Dave Premack. This is all an evolving picture; nothing is static here. Dave had gone off to Penn and I'd gone to New York University. I was beginning to work on neurologic patients as part of that new job and set that up in the book a little bit. The question was, how could we successfully communicate with a totally aphasic patient? That meant their left hemisphere had had major brain damage, and the person couldn't seemingly speak or think or understand language. But they had a whole other right hemisphere that was undamaged.

Could we use these methods that Dave was developing on the chimp for the right hemisphere and get a communication going? We started a series of studies together at NYU on patients, with a graduate student at the time, Andrea Velletri. We took it a small step forward before we didn't do it anymore. During that time, I was getting interested also in human patients, and in patients with focal disease, again, with the idea of trying to specify with greater specificity where particular functions were in the brain. Could you get smaller lesions that could hit more circumscribed areas? Of course, that was the classic field of neurology. Before that, the great neurologists of the 18th and 19th century, that's what they did. They would find strokes and look for deficits. There was a background for that work, for sure, and we were going to do it through the disconnection model and some new thinking, which contributed to it. It's a hugely important field.

ZIERLER: Mike, tell me about your interest in reaction time, during this period. What does that mean in the context of split-brain research?

GAZZANIGA: The simplest idea was, if something's going on in one hemisphere, it's got to take time to get over to the other hemisphere for further processing. By using reaction time, could we track the flow of information? Yes, it seems to be first on the right, and then it's going over to the left, and that takes so many milliseconds. In that way, we could specify the flow of information from one center to the other. It's a hard task because it doesn't take much time.

People worked on this for years, including Berlucchi, who I mentioned to you earlier. It became a common approach in the field to use reaction time as a technique to get at trying to detect the flow of information on any given perceptual or cognitive act.

ZIERLER: What does this flow into? What is the next set of questions you can pursue as a result of this focus?

GAZZANIGA: What are we all trying to do here? We're moving along with little baby ideas about how we can study this thing, like flow of information, spatial location, timing. What did we have in those days? We had RT (reaction time) for timing. Then came in, a few years later, event-related potential. You could take signals off the scalp, do a huge amount of processing on it, take the EEG basically, and turn it into a method for tracking flow of information around the brain. Steven Hillyard a brilliant Caltech undergrad who worked in Sperry's lab became a world leader in this field. You could study things like attention, how attention influenced the flow of information and the speed of processing. All these things were grabbed onto as soon as they became available enough to use, to pursue this rather simple knowledge that we were trying to figure out: The underlying circuits of acts that we know are going on, perceptual-cognitive memory, short-term memory, and so forth. Then we hit the ‘80s where all the brain-imaging techniques emerged – CT and MRI – and then functional brain imaging, then PET scanning, and functional MRI, and there's many, many others now. Yet, in some sense, it's all trying to just figure out how the networks are activated and what the internal architecture is to produce behavior, cognition. To this day, we don't know if we're searching with the right metaphors. Might be happening in a completely different way, and we haven't caught it yet. There was just a small meeting here at Santa Barbara—I wasn't able to go to— where they were looking at this very question. What are we doing? Have we asked the right question?

That quickly evolves into a discussion of the role of dogma in science, that an idea gets out there and it stays out there, because there's all kinds of forces to keep that idea out there, when it may be the wrong idea. It's not the underlying data or the quality of the work—nothing wrong with that. Everything was done right. But it's the way it's looked at. The theoretical context of all that data might mean something else from a different vantage point. Those are the kinds of questions that really haunt scientists, of course: that they're looking at it within an incorrect framework. The good scientists are fully aware of this, but tend to try to put it aside—because you can't function if you're constantly wondering if you're doing it correctly. But nonetheless the good scientists are wondering and wanting to know about new ideas and new ways of looking at things in general.

ZIERLER: Mike, tell me about your decision to move to New York University Graduate School in 1969.

GAZZANIGA: I had gotten to know, while at Santa Barbara during my first stint, Leon Festinger. Leon Festinger had been at Stanford University, where he was Mr. Psychology.

ZIERLER: What was Festinger known for?

GAZZANIGA: Social psychology, cognitive dissonance theory. Have you heard of that? That's his, and he was one of the giant intellects in the field, no question about it. I mentioned Chuck Hamilton to you, and he had gone up to Stanford upon graduating from Caltech and had gotten Festinger interested in some of this eye-hand coordination work. At some point, Festinger calls me up, and says, "Why don't you come up and talk to my seminar?" "Sure!" I go up to Stanford. Festinger's seminars were held in his living room, where you were placed in the hot seat, and everybody was sitting around having drinks—as I remember it. Then for two and a half or three hours, they grill you about everything you have to say about this topic, with great interest. Not a negative grilling; just wanted to know every detail of it. I said, "Wow! That was great. That was a great experience. This guy's great." We became very close friends.

Then he moved to The New School in New York, and they were starting a joint program between The New School, Columbia University, NYU, and CCNY. There was a job open at NYU, so Festinger calls me and says, "You should come to New York, and give NYU a shot." I said, "Well, I don't know, blah, blah, blah." He came out to visit in Santa Barbara. I had just finished building this beautiful redwood home in the oak trees, and it was just the last word. I remember Leon comes over to the house, we have cocktails, and I say, "Leon, a New York City crummy little apartment versus this?" Leon takes a puff from his ever-present Camel, and says, "Well, this would cost a lot of money in New York City." With one line, I realized, you want this? Fine. But New York City, there's magic back there. I said, "Okay." So, we thought about it, and we went. I've never regretted it. It was a great experience. But then it became too much with three kids, doing all the commuting I was doing. I then moved on to Stony Brook and took a job there, where we could live in the town with the university. Then from there—I don't want to get ahead of myself—Cornell Medical School and its neurology chairman said, "We need that neuropsychology stuff." "We need somebody here to do that, so why don't you come to Cornell and do it?" So I did.

ZIERLER: Mike, you said that the term "neuroscience" really got going in the ‘70s. Now that we're at this point in the narrative, what was happening that sort of compelled the use of this new term?

GAZZANIGA: There were all kinds of advances in neuropharmacology, neurotransmitter research, and people were seeing how these related to moods, issues, felt states, just basic neuro, but also to just basic synaptic function. There was a big push from people like Eric Kandel and others on the importance of a synapse – focusing on a simple synapse, in simple systems, and figuring out how memory worked. All that was going on while all of the classical conditioning work was going on. Basically, people got together and said, "This is all neuroscience." They came up with the term "neuroscience." They had the first meeting in 1971 in Washington. At that meeting, 1,000 or more people showed up, I think. I remember I was invited to give a talk and then, bingo, that was it. That was the meeting, same as now, except 40,000 people go to it today. It's interesting you raise this question about terminology because my chairman at Cornell in the neurology department was Fred Plum, a very famous neurologist, and he was very involved in the development of medical bioscience. He was a clinician who cared about the basic sciences and how they got developed. He would confide about conversations vis-à-vis how these things like words defining the topic were very important from the Washington vantage point of what to fund. What are we doing here? What is all this stuff? There was probably another reality of science politics that these guys dealt with. They saw the importance of naming something, giving a coherence to it, so the people who don't know anything about science, but are the ones writing the checks, could figure out and keep a handle on what was going on. I don't know if that kind of thinking was going on, but I had a sense from Fred that those were the kinds of conversations that did occur.

ZIERLER: Now, your time at Stony Brook was good? It was good to be out of the city?

GAZZANIGA: Oh yeah. Stony Brook was where probably my most famous student, Joe LeDoux, joined the lab and got his degree. He helped me primarily, fundamentally in the launching of the East Coast split-brain series. He was a very ingenious guy. That was a very positive experience.

ZIERLER: What was your focus in the visual systems at this point? What were you looking at?

GAZZANIGA: I would say, the thing that interested me about visual systems came later when I was at Cornell and Dartmouth Medical Schools, a little out of sync with the Stony Brook thing. I became doubtful of something called blindsight. But while at Stony Brook…

ZIERLER: You mentioned the significance of LeDoux's research. Does this lead to your coauthoring The Integrated Mind with LeDoux?

GAZZANIGA: LeDoux was involved with the original work on the East Coast series of a split-brain patients. Most of them did not have the kinds of complete surgical section we needed to show the split-brain effect. Then patients started coming in that did show that effect, and he was there for that, and he was part of it, as much as anybody. We decided to capture that in the book, The Integrated Mind. LeDoux hadn't yet started his really groundbreaking work, studying emotional behavior. He was at Stony Brook, and he came with me to my first year or so at Cornell. Then he decided he wanted to go into animal work and study emotional behavior, which he did in his now famous beautiful work. Matter of fact, he just came through town. He was part of this meeting I mentioned, and we had a wonderful dinner. He is a top-notch guy.

The Origins of Cognitive Neuroscience

ZIERLER: Mike, I think a perfect narrative picking-up point for next time is your decision to move over to Cornell University Medical College, and specifically the development of cognitive neuroscience. Maybe my last question for today is, how did that term "cognitive neuroscience" come into being, and why was Cornell the best place for you to pursue this?

GAZZANIGA: Again, it's one of these things that happens. You meet somebody. The person I met at Cornell was the very famous psychologist George Miller, who was a professor at Rockefeller, which was a driveway away from Cornell. It was right across the street. We met and became fast friends. We used to end many a day at the Rockefeller bar, and we would have a drink, and just put everything together. I think I mentioned this last time. Anyway, I kept saying, cognitive science doesn't have any neuroscience, and neuroscience doesn't have any cognitive science. We would agree to that.

ZIERLER: [laughs]

GAZZANIGA: One day, we were getting into a cab going to the Algonquin Hotel, and as George put it, "I thought of the term, and you did it." [laughs] I said, "Wait a minute, I thought I thought of it." "No, no, no, no." [laughs] Anyway, it happened between us because of our collaboration: Cognitive science needed neuroscience, and neuroscience needed some models to explain, "What is it we're trying to understand here?" It's two different layers. It's the genotype– phenotype question. It's the mind–brain question. It's that gap between the physical and the mental—and what is that? Have we framed it correctly yet? I don't know if we still have yet, but we're working on it.

ZIERLER: Mike, last question for today. Did it feel like cognitive neuroscience was an outgrowth of a developing field or was it brand new? Were you trying to create something almost out of nothing?

GAZZANIGA: I think these things all have extended origins. There was certainly a field called neuropsychology, which meant what kind of psychological deficit occurred with a neuro dysfunction. So that was there, and there had been the lifelong work of Wilder Penfield, very famous of McGill University and the Montreal Neurological Institute, and then all the classic neurology out of Europe and even some American-led. Cognitive neuroscience was the next layer of just saying neuroscience. Neuroscience had simmered everything down to the parts, the building blocks. Cognitive neuroscience was letting cognition in, not just behavior, it was letting abstraction back in. Can we get to neuromechanisms of abstract thoughts? Can we get the neuromechanisms of problem-solving? Can we get to neuromechanisms of subjective reality? Does that have a neuro basis? These are all fair questions under cognitive neuroscience. What we were saying was, it's okay to study these things. We're a long way off from understanding, but it's okay. I think that was the underlying motivations to try to recognize that we've got all these new techniques available to us, and they're coming in more and more each year. We want to get to these other questions. So it's very much alive.

ZIERLER: Mike, that's a great place to pick up for next time, when you arrive at Cornell University Medical College, and you pursue these questions, and what came of it. We'll go from there.

[End of Recording]

ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It's Thursday, May 23rd, 2024. It is wonderful to be back once again with Professor Michael Gazzaniga. Mike, as always, it's great to be with you. I look forward to continuing the conversation.

GAZZANIGA: Great. Thank you.

ZIERLER: We're going to pick up—you explained last time this wonderful idea that there wasn't enough cognition in neuroscience, and there wasn't enough neuroscience in cognitive science. So maybe a bit of institutional history. Was Cornell University Medical College, was that the place to try to merge these disciplines? Was there anywhere else where you could have pursued this?

GAZZANIGA: Oh, sure! Let me paint a little of the picture. The Cornell Medical School, New York Hospital had probably the finest or one of the top two neurology departments in the world. It was led by Fred Plum. His colleague, Jerome Posner, co-chair actually, was across the street at Memorial Sloan Kettering. It was all a big medical complex there in New York City, and they were the outstanding leaders. They wrote a book called Diagnosis of Stupor and Coma, which became a classic. First-class, but they didn't have any neuropsychology, which is what it was called prior to cognitive neuroscience. One thing led to another, and they found me out in Stony Brook and said, "Why don't you come here?" So I changed my job—it was a change in life too, for a personal reason—and took on the Cornell job.

Then I'm there in a vastly new experience from a psychology or a biology department into an actual medical department. There are worlds of differences between them all. There's an immediacy and an urgency to the medical scene. People are dying, people are sick, people are this, people are that. It's just go, go, go all the time—and with energy, too, because they have a staff of young people, the residents and the interns, who are there to learn and serve, and they want to know stuff. Fred Plum, the neurologist, was saying, "Okay, you teach them the psychology part, the behavior." With basically no other credentials than that, we just started doing it. Then the happy coincidence was that right across the street in that medical complex is Rockefeller University, and as I have already mentioned it had the great cognitive psychologist George Miller there, who was world famous, one of the founders of psycholinguistics, and much more. We started interacting and, before you know it, we were training each other. Before we knew it, we came up with this idea—as you just stated—that cognitive science needs some neurology, and the neurology needs some cognitive science. That's how the idea got born. That could have happened anywhere. Life if it teaches you anything, it teaches you, don't play tennis with a bad player. Make sure all the people you play against are better than you, and you'll learn something. That certainly was the case on that corner. Everybody was really good, and you played at as high a level as you could to keep up with them.

ZIERLER: Mike, you've already explained how each discipline needed each other, that there was something missing in both, and the idea was to merge them. How did you go about executing that plan at Cornell? What was your first step?

GAZZANIGA: By doing; by doing. There's a thing in the tradition of medical schools and medical training called rounds, where the professors take the residents around every morning to see who has come in the hospital, talk about each patient, using that as a training episode for the professor to transfer their knowledge to the residents and interns involved. What happened was I was added into that mix, as it were, as one of the people to go on rounds, and to offer, when I spotted something, a psychological way, an experimental psychological methodology, that could be used to test or aid in the diagnosis of whatever they thought they were seeing—whether it was a language disorder or a memory disorder or an attention disorder. It was not common in those days for these methods to be brought in and applied to the patients. Pretty soon, the residents— who were outstanding, they were probably the outstanding neurology residents in the country— man, they just took it on. They loved it. And my lab, full of psychologists, was a huge part of the development. Jeff Holzman, John Sidtis, and my future wife Charlotte Smylie were all making studies happen along with the neurology residents, such as Bruce Volpe. Before you knew it, we were all doing experiments on the medical floor. We cleared out a spare room where people were storing stuff, put up our testing tables and put in our projectors. Just like that we had an experimental lab right there in the midst of the patients who were showing all of these wonderful—from a science point of view—disturbances of consciousness. Our task was to try to figure out what it was, how to quantify it, and how to describe it, so we could understand it with greater depth. It just naturally occurred, so it was just there, it was just ready to be done, and so we just got going and did it.

ZIERLER: Now, quantifying it, what does that look like? What are you actually counting, and how are you analyzing it?

GAZZANIGA: You can do everything from simple tests of short-term and long-term memory. You can look at rates of forgetting. These were all the traditional ways of doing it. A big investment of time and energy at that point was in the study of attention: Could people switch their attention to increase their performance on all kinds of tasks? Were people impaired at switching their attention? Then there were these bizarre syndromes, such as neglect, which I talked about earlier. As you're looking at me, you wouldn't see half of me because your attention was completely focused on only half of space. What is that? Can we use that condition to understand something else, something fundamental about how the brain sees and understands space in general? We tested several patients with neglect using the apple and orange test, described earlier, right there on the floor as they came through. You'll recall that they still denied seeing the orange, but were able to point to the word "different." That means that visual information is getting in and is being processed at some level of the brain. Decisions are being made about information from the neglected left visual field, but still the patient is only consciousness of the stuff in the right visual field. That begins to tell you, of course, maybe we can study what most of our brain processes are. Maybe we can study the subconscious, the preconscious, or however you want to state it, by using these techniques of tracking the information by simple little behavioral measures, but also by setting the test up in a way where you could infer if, when, and where these things were happening. You could see, yes, something must be happening, the information's in there somewhere. It's getting done somewhere.

Then you would set that up, and then try to use other technologies, as that story unfolded, to detect where and at what level of the brain that information would be processed, and so forth. It became tricks that were just not in the training of the residents combined with the resident's training about where these lesions were located and how to manage the patients. It became just a flow of training, mutual flow of training between people with different backgrounds. As I said, I ran a lab with several postdoctoral fellows who were experimental psychologists. They soon became the fast friends of the neurology residents and published many papers together. There had been, of course, the classic field of experimental neurology before behavioral neurology, for sure, going on for hundreds of years. But these new test strategies that people were developing were brought in to bear, and you could push the issue further, into a deeper understanding.

ZIERLER: Mike, was there a sense that, as this field was developing, were you in a race? Were you and your colleagues in a race with scientists at other universities to make these discoveries?

GAZZANIGA: I don't think of it that way. We were in a race to get some things done that were interesting. You were in race with yourself.

ZIERLER: There wasn't a culture of getting scooped or trying to scoop others?

GAZZANIGA: No. Maybe that was rampant in molecular biology at the time. I mean, they slept in their labs. A lot of that was also going on at Caltech. It was hustle, hustle, hustle because things were breaking so fast in molecular biology. Experiments could be done so quickly. The field of early cognitive neuroscience—or neuroscience, for that matter—is slower, it's more demanding, and the details take time to acquire. It's not running molecular experimen and getting an answer. No, it was gung-ho, but it wasn't that. I know what you're referring to, and it didn't have that feel to it; at least, it didn't have it, to me.

ZIERLER: Mike, as you were working and developing to merge these fields, how did that change your thinking about split-brain research?

GAZZANIGA: The split-brain thing was so clear. The disconnection effect: one side didn't know what the other one was doing. People wanted to know, could we use the clinic, the neurologic clinic, where people had focal lesions, to confirm what we thought was, say, a property of the right hemisphere or a property of the left hemisphere? Could we find patients with a lateralized lesion with a specific deficit? Let's say you thought the right hemisphere was dominant for certain kinds of visual-spatial processing. We certainly found that from split-brain work. Then the question is, well, if you have a lesion localized, which part of the right hemisphere could we determine really was managing that particular perceptual or cognitive skill? Could you chase it down within the hemisphere by studying focal disease cases? That brought you right into the neurologic clinic, and lots of studies were done along those lines. It added a dimensionality to the standard structural/behavioral kind of approach. This was right during the early days of brain imaging, which, of course, just blew open the door! With the new scanners, one could scan people with normal brains and see which brain areas became active when carrying out a specific task that was presented to them. And different types of scanning were becoming available, everything from positron emission tomography, to functional brain imaging and later to other approaches.

The approach is to give the normal subject just a normal old psych problem and see if you could figure out where in the brain they are solving it. In a normal brain you're not studying brains subsequent to epilepsy or some other problem that may have caused redistributions of functions. With the emergence of brain imaging, you can put normal people in the scanner and get a story that would be interesting. That was just beginning to happen and going to happen in full force, and continues, of course, until this day as a major approach. To think that was going to happen was unheard of. But now it happens routinely. I see it as a continuum. First of all, we were fortunate enough to discover the split-brain story when these patients came along. Second, you could lateralize stuff from one brain hemisphere to the other and look at what each hemisphere could do without the other knowing about it.

Third, being in the general clinic, which allowed us to look for particular areas within the hemisphere to confirm and modify those ideas, and then the next step was to put normal brains into the story, using all these new technologies. That was the basic underlying flow. In addition to all that, of course, there was the neurophysiological advances; people just taking electrical signals from the skull and developing things called event- related potentials that could see how the brain's electricity would respond in response to stimuli that were locked to a particular time base. The idea was that event-related potentials studied the temporal processes of information flow. Whereas these brain imaging studies I've been talking about were going to localize, were going to be the spatial. This is where it's occurring. Then the temporal would tell you when it was occurring in the processing of any particular thing you were studying. That was the chemistry and excitement in the early days of cognitive neuroscience.

Psychiatric Considerations

ZIERLER: Mike, working more closely in the clinical setting, watching patients go from experiencing brain damage, and going on the road to recovery, what was the research value in that of watching the brain heal?

GAZZANIGA: People who have a brain injury always want to know if they will return to normal. If you have a stroke or a tumor, and let's say it's in a language zone in your left hemisphere, you want to know when that stroke resolves or the tumor is removed, how much of your normal language and speech is going to return. It's obviously deeply important to a person. Then follow-up questions would be, well, are there other parts of the brain that if you carefully look at this over time might take on those functions? Does it matter what age you are when the insult to the brain occurs? Is there a greater chance of recovery if that happens when you're younger versus past certain ages and even into adulthood? Those issues had been looked at but, again, with the new methodologies, you could look at them more closely. There were stories with some evidence for unexpected plasticity in some brain areas. Then there were other stories that it wasn't such a great prognosis. Depending on the size and site of the lesion, you could predict— you became better at predicting whether there would be any recovery. It became part of a large clinical assessment that would play into the caring for and the wellbeing of the patient. Trying to assist the recovery from stroke is still a big, big, big issue in neurology and rehabilitation; a huge issue.

ZIERLER: Mike, in creating this new field, cognitive neuroscience—of course, psychiatry is an older field, much older field—what was the impact? In what ways were psychiatrists paying attention to this, and how was it changing their work?

GAZZANIGA: It depended on how your training went in psychiatry. There were psychiatrists who were very into the neurologic aspect of disease. The psych residents would train in the neurology wards, and the neurology residents would spend time on a psychiatric ward. There was a mixing of disciplines because whether you have a psychiatric disorder or whether you have a neurologic disorder, people realize that the brain's involved in both cases.

We have to have a greater understanding of the brain part of the story to help both. That was a very big part of the training. But, in general, the nature of psychiatric illness is just so different from the kind of thing you see, by and large, in neurologic settings that the two have a way of staying split apart, each field to different specialists— specialists on one versus the other. I think that pretty much remains today. Although, I have to qualify that because there are people who are very skilled in both domains. But, by and large, the psychiatrists take care of the mentally ill people, and the neurologists take care of focal disease. Now, of course, a lot of psychiatric diseases are neurotransmitter-based, which is a physical disorder. But it's just a subtler kind of disorder than, bam, a hole in the head or a tumor or a stroke or a degenerative disease like Parkinson's. In most of those cases, there are extensive lesions, but the overall neurotransmitter functions are usually more or less normal. It's just a different thing. It's a different animal.

ZIERLER: Mike, tell me about the origin story of the Cognitive Neuroscience Institute.

GAZZANIGA: That came again from the interactions there in New York. It started at Cornell in my interactions with George Miller who was, again, at Rockefeller. George was really one of the deans of American psychology and cognitive science. I don't know. He might have been the top guy in the world. He was one of the statesmen of the field. He was always looking to help the field expand cognitive science; absolutely committed to it. The Alfred P. Sloan Foundation, which is a New York foundation, was intensely interested in cognitive science.

George became one of their advisors. As we got to know each other on the neuro side, which was new to George—he hadn't experienced that until we met there at Cornell—he felt that they might support something. I put together a consortium of people in New York: Leon Festinger at The New School; Stan Schachter up at Columbia University; Al Bowker at The City College of New York; George from Rockefeller, who was transitioning to Princeton at the time, and me.

We started this think tank kind of thing, and we were funded by the Sloan Foundation, and we started holding meetings. We started talking up the field, and we had workshops, and all that comes with the development of a field. George had been through this in his long career in things like math, psychology, and cognitive science itself, language, and psychology. He knew how these things evolved to get them established as part of academic life. He saw me as a person who was willing to put the work in on getting this done for cog neuro, well, it became known as cognitive neuroscience—and we did, that's what we did, and it still exists today. It's out of that initial effort that we started the Journal of Cognitive Neuroscience. We started a funding program, where we teamed up with the James S. McDonnell Foundation, and we were part of a group that helped evaluate four or five different areas in cognitive neuroscience. I think we went on for two or three years of study. Four or five times a year, these groups would meet, and they would have people present cases, and how could this best go forward, and what should be funded? Then, finally, at the end of all those deliberations on that task, the McDonnell Foundation teamed up with the Pew Foundation, and they had started to contribute money to these various subareas. It's a long road and a winding road, as George used to say. But that's how, in fact, actually, it kept going. It kept going because people wanted it to work. There was no one saying, well, that's a waste of time. Everybody realized that trying to figure out how the brain does all this is one of the great intellectual challenges of our species. There are all these new methodologies coming along now, and all these new techniques, and all this talent, sure, this should be supported. That's a big part of the story. But I would add to that. There was also the steady hand of these guys who knew about how science got going, who didn't flip out at the slightest little bump in the road. They's say: no, no, these guys are working hard. They're doing a good job. Having that kind of leadership above you, and having conversations we weren't privy to but we knew the result of, which was support, was a big part of the success of the field.

ZIERLER: Mike, as you look at the conferences, the members of the Institute, how was that a microcosm for generally the growth of the field?

GAZZANIGA: My observation on that would be that I have a pretty good eye for who wants to make things work and who doesn't. The old sour grapes over there, just don't invite them. Sure, you can be skeptical. Everybody's skeptical! This is the world's hardest problem. But you see what is trying to be done here, and you want to encourage it in every possible way. You want the people to be real smart, of course. That goes without saying. Putting the meetings together in a positive context, with people who have done the work—people who have all kinds of different opinions about it, but who are positively seeking a goal of advancing—is really, really critical. I think, for the most part, we did that in our study groups. There was a study group on memory, a study group on the nature of motor control, a study group on higher cognitive processes, a study group on attention, a study group on emotion and cognition, a study group on memory and learning, and these would each have five or six members. They would then invite authorities in from all over the world to hear their view on how this new field of cognitive neuroscience is going to best go forward. So, lots of foundational work, and it still goes on. I mean, the field's launched. It's everywhere now.

Assessing where you are (and writing it down) was a big part of cognitive neuroscience when I took on what are called the Summer Institutes in Cognitive Neuroscience. Every summer, we brought in 70 students from various scientific fields and from all over the world for two weeks, and we had lectures given by investigators from disparate fields related to cognitive neuroscience all day long, and labs, and hands-on. We brought in kids who had never seen a brain. They'd hear about these brain areas, but they didn't have a geometrical sense of what we're talking about. It was absolutely foreign to them. We had arranged for brain dissection labs by getting human tissue and having some of the great human anatomists come and teach these kids. You could have heard a pin drop in this room! It was an exciting blending of fields. We did those for four years, every summer for four years. Then on the fifth year, we extended the workshop to three weeks. We picked the top 20 students from the previous four years and brought them to Lake Tahoe. Then 80-100 scientists would come lecture, but they had to bring with them a summary paper, a statement of where their art is. We did that, we've done it now for over 30 years. And we then published the papers with MIT Press for all to see. We now have six volumes, 1,400 pages long, taking stock and assessing these various subfields. There'd be 100 chapters. It became quite a deal to become invited to give an assessment in their area. It just kept the train on the track. Here's what we know, here's what we're growing into, and so forth. All that is very important, I think.

Computers and Information Storage

ZIERLER: Mike, by the mid-1980s, tell me how you got interested in thinking about information storage in the brain, and if you were influenced at all by all of the innovations that were happening in computation.

GAZZANIGA: Information storage is one of the big problems; a big issue. How on Earth does the brain store information? How do you access it? What is the mechanism? [laughs] It's still the big question, and so big that in the early ‘80s I held one of our meetings, sponsored by the Cognitive Neuroscience Institute. We held a meeting. I discovered—this is a little side story—I discovered how to get the best people to the meeting, where you want to have these discussions. It turns out the secret to it is, pick a place that people want to go to.

ZIERLER: Of course! [laughs]

GAZZANIGA: So instead of this meeting costing this big chunk of cash, you'll only have to give them 1,000 bucks, because they all have money from other sources. You want 10 people no more. You want to each give them a half-day to tell their story and interact. One of the meetings was in Moorea, off Tahiti. The first person I called up—I'd gotten to know Francis Crick down at the Salk Institute. I said, "Listen, we're having this meeting on the neurobiology of memory. What's going on with memory?" He was just getting involved in neuroscience. "In Moorea, blah, blah, blah, this week." "Fine! Yes!" Boom! Hangs up the phone. You go onto the next guy, and it takes you 10 minutes to put together a meeting of 10 people because they all want to go. If you'd said, "I've got a meeting in Omaha in February." "No, no, no, no, no." [laughs] That's just a reality. If you're a one-horse operation like we were, then you want to reduce the time you spend on that kind of stuff.

Anyway, we held this meeting and Francis was there. It was prompted by a young psychobiologist, a colleague now my age, Gary Lynch from UC Irvine. He was working with people at Caltech on the nature of the synapse and information storage. There was lots of interest in the synaptic mechanism. Eight or so other people came to this meeting, and we met for a whole week. The design of the meeting and all these meetings we held is the person, whoever is the speaker, has the floor for either the entire morning or the entire afternoon. The whole idea was to not give a slide talk. The whole idea was to just start talking, because everybody knew what everybody did. Then there were all the interruptions and questions that everybody always wanted to ask whoever was speaking. It turned out to be a great model for truly interactive, challenging discussions on various things, one being the question of information storage. A book came out on it, a little book, trying to capture it, and so forth. I think these things are extremely important, and they catalyze relationships. They catalyze discussions you can't imagine that you would otherwise have. The other thing we did, we never over-organized them. I think, during the whole week, there may have been one or two common meals. The rest of the time, people just paired up as they chose and did what they wanted to do. But during the work time, there was a two and a half, three-hour session where everybody was together twice a day. It was great.

Fabulous meetings. The unexpected was always happening. In Moorea, for example, Crick brought along a young colleague at the time, Geoffrey Hinton, now, of course, known as the godfather of AI.

ZIERLER: Mike, thinking about memory research vis-à-vis information storage, is the right way to think about this, information storage is literally where the information is stored, and memory is how to access that stored information?

GAZZANIGA: The field has been captured by real simple models of how this might occur—where information comes in as short-term memory, and how it gets transferred through some process into long-term storage. Then somehow this information gets looked up in these long-term storage sites, gets retrieved, and manifests itself into a memory. There are all these computer models, simple computer models. The early people looking at this, even in our modern times, just had this overwhelmingly simple view. It must work some way like that, like a simple machine. Now, it's a very complex question, and people are trying to think of all kinds of different ways. It may be that the information's coded in another way. Maybe it's coded through oscillations in the brain, or maybe coded by different frequencies that different parts of the brain set up and interact in a certain way, or coded in some way that's in a bioelectric field as opposed to the cellular synaptic changes. There are all kinds of interesting studies for all these points of view. How it's going to come together into how it actually works, I think, is utterly an open game now. It's one of the great challenges to try to think about how it's going to work. The simple little computer models of, well, you've just got to set the ones and zeros in a particular way and that's where the storage is, then you just go retrieve it and it's there for you—to my mind, that got us going in the modern time, but that's not where we are now. I actually think it's an extremely exciting time, and I think the field is waiting for a big idea on how this could work. I think it's going to pop out here, I would say, in the next five to ten years.

ZIERLER: Oh wow! What would that look like? What are you waiting to see? GAZZANIGA: I don't know. I don't know. I don't know. That's the prudent thing to say. ZIERLER: Okay. Fair enough.

GAZZANIGA: But I think there's a sense, there's enough sense of wondering what another model could look like that stuff will come out. I can tell you—let me think here for a second. About six or seven years ago we ran a meeting here where we were looking at information storage—this very question—and the biologic basis for it. We had one of the real thinkers on this issue, Randy Gallistel from Rutgers. He was challenging the then dominant notion, best represented by the Kandel research program, of whether you can figure this out by looking at synaptic processes and LTP and the whole storyline there. We had this meeting in which there were other people with different ideas about how the information was stored; very good scientists. It became clear at this talk, at this workshop, that when you really open it up to all ideas on the table, that tight little stories with our metaphors just weren't capturing enough. Now I think the field is open. I don't know if you saw in the last week or two that the distinguished neurobiologist at Harvard, Jeff Lichtman, published the neuroanatomy of one cubic millimeter of cortex. It's unbelievably complex. It's got a gazillion synapses (actually 150 million). Oh my God! He gives me a headache thinking about it. But he got all of them. There's a picture. This guy's done incredible work. But, okay, how does it all work? I mean, now you've made the problem exceedingly daunting by showing how complex the micro-connections are.

Again, how is it going to work—how's the machine with a gazillion parts going to work—you know? Still, I think big things are going to pop forward here in the next bit of time.

ZIERLER: Mike, thinking about information storage, memory, research, when does consciousness become something that the field considers can be seriously studied, where it's not all hand-waving, and we're not even sure if it exists, and all of that stuff?

GAZZANIGA: It's another live topic. The philosopher Dan Dennett was one of the current philosophers who really thought about this a lot. Of course, he was more in the camp that consciousness is an illusion. What happens is you have this complex system working, and when it's doing its thing, what it's doing is producing this thing that makes us feel like we're conscious. But if you try to go find it, it just all comes out of the interactions of this complex system, and so, just like illusions are real, they feel real, but you can't find them anywhere. Take the Müller-Lyer illusion for example. One line is definitely longer than that the other. No, it's not.

As you go to get hold of it, you can't find it. Then there are people who think, "Oh no, that's crazy! That's a quality of a subjective reality. It feels real. It's got to be real. We're just not smart enough yet to figure it out." They have models of ‘where the brain thinks' as a part of it, what parts of the brain are part of which aspects of consciousness and so forth. It's very much being discussed. I find it a very frustrating topic because I think it's one of those topics where people with high verbal skills become dominant because they can talk anything. They're skilled at taking an abstract idea and running it around the barn, as it were. But when I get done listening to those talks, I want to build one of the things they're talking about.

ZIERLER: [laughs]

GAZZANIGA: It never can come to that. It's a big question. I have my own ideas on it, and I wrote a book about it. But the phenomenon is, everybody would love to be able to say something absolutely solid about it in terms of mechanism. But when you're facing the issue that maybe it's not there, the mechanism is an illusion, it's a very hard game to play.

ZIERLER: If it is an illusion, what does that even mean?

GAZZANIGA: Yeah! I have the same question. Well, it means it's an illusion. That's what it means. You have no problem with visual illusions, right? You see them all the time. It's a mirage. You swear it's there. You swear your life on it. Roger Shepard had some wonderful examples of this, the perceptual psychologist at Stanford, who then went to Arizona. Have you ever seen his turning tables illusion?

ZIERLER: Oh yeah!

GAZZANIGA: It can drive you nuts. I mean, that's it, come on, I see it! But it's not there. Take that reality—that's demonstrably an example of an illusion—and just say, well, it goes all the way up to this thing we're calling our subjective self. So, it's tough. Then the split-brain story comes along, of course, and doesn't help matters in the sense that you undergo this surgery and, all of a sudden, there's two of these systems in your brain that we can separately access without one knowing about the other. What? Wait a minute! What are you saying? That was really part of the big discovery with split-brain research. You could have two subjective thinkers as a result of a surgical disconnection of one part of the brain from another. That's big stuff. What does that mean? Well, then you're off and away.

The Problem with Illusions

ZIERLER: Mike, you've emphasized the centrality of technological advances in imaging. Is part of the problem with consciousness that we don't know what to image or where to look?

GAZZANIGA: We don't know what the question is. In an experimental sense, we want to go look for the molecule that binds with this cell when we see this happen in the behavior of the cell. That's a definable problem, and you can go do it—and people do that kind of thing. It's hard work, but brilliant things come out of it. Here, I want to study the aspect of the self when I feel annoyed. That's a conscious state. You're annoyed or you're happy, or whatever it is. The minute you start looking for the circuits for those things, you get confused real fast as to what you're doing and what you're thinking about. My student Joseph LeDoux—a brilliant guy—was just pointing out the other day how, in some of his earlier work when he started working on the emotional system that he discovered that a part of the brain, the amygdala, helped manage fear responses in the rat. That's how it was first reported, the fear mechanism processing started in the amygdala below the cortex, and there was this whole fear part of the brain.

As he studied the thing over the years, however, he realized that's wrong. It's an avoidance mechanism that's built into the animal by evolution. We called it fear. Then what happens? People pick up this folk psychology term and start referring to this thing as the fear circuit. We're looking for the fear circuit in the brain. No! We tripped ourselves up with our own terminology about what's going on in this very specific instance. It's really avoidance of a noxious stimuli. People say we need a whole new ontology, a whole new vocabulary for how we talk about these things. I think there's a whole lot of really smart people who are saying we've got to redo a lot of rethinking here about how we approach these problems.

ZIERLER: Mike, here's a question that's hopefully easier for you to answer. Tell me about your decision to move over to Dartmouth Medical School in 1988.

GAZZANIGA: That was practically motivated in two ways. One, my son was born, and that gave my wife and me two babies living in a New York apartment.

ZIERLER: [laughs]

GAZZANIGA: Get out of town, man! [laughs] Secondly, I had a whole series of patients that we were studying who came from Dartmouth Medical School—so a second series of cases that were referred to as the East Coast series. There was the Caltech series and the East Coast series. We were going up there all the time to test the patients, and at one point, we had a mobile home. Then we built a lab up there in a house. Dartmouth Medical School said, "Why don't you just move here and do what you're doing at Cornell here?" I joined the psychiatry department there and opened up their program in cognitive neuroscience. It was a great period of time, and I stayed there for four years. Then I'll just tell you the next step.

The University of California, Davis started approaching me about coming out and setting up and starting a Center for Neuroscience there. I didn't know what to do. But, long story short, I finally decided I wanted to try something like that. They gave me a ton of resources, and I wanted to try and build a center, built up from cellular work all the way up to cognition. We decided to take that job and moved out to Davis for four great years. A great place, great institution. Then Dartmouth called me back. My alma mater said, "No! Now you've got to come back to the college part of our institution. Forget those medical school guys. Come over here to the arts and sciences." So, I did. All were good moves. Terrific people at both institutions.

ZIERLER: Tell me, both at Dartmouth and back at California, your experiences in institute- building and gathering resources.

GAZZANIGA: UC knows how to do this. They're a big research university. The trick to UC is to fall into the hands of an administrative unit that works with you instead of against you. [laughs]

ZIERLER: Sure! [laughs]

GAZZANIGA: By against you, I don't mean against you; I just mean kind of inert, and doesn't do for you. At Davis, I had these fantastic administrators above me. You could call them up and, in five minutes, they would say, "All right, yeah, we can do that." Then you had to go do all the paperwork, but you knew what the answer was: They were going to approve it. That really allows things to move along. Then the colleagues at Davis were great. When I first took the job, I tried to hire a fancy couple from Yale. Great senior people, and they're great, but it didn't work out. I learned something with that: Fancy scientists probably have some fancy graduate students coming through the lab that are doing all the work. So, I bet those students were a good bet too.

UC likes to hire assistant professors. They like to raise their own. Anyway, I switched my strategy to hiring assistant professors out of the great labs, and it really paid off. It was a good way to do it. They came up with the money. I also needed space when I started. I really didn't have space. They said, "Well, Research Park is developing over here in Davis." I said, "Oh, yeah, okay." Then I went for a drive, and I saw this building with a for sale sign on it. Oh, I stopped, and it says, "Call us, and we'll finish it up the way you want it." I called up the then provost and said, "Bob, I got this thing and it's for sale, and maybe this could solve the space problem." He said, "Let me put you on hold." He puts me on hold. He comes back, literally, five minutes later, and says, "Okay, we can do it." I thought, okay, this makes life easy.

ZIERLER: Yeah. [laughs]

GAZZANIGA: That was a great experience. Dartmouth has always been very good about these matters too. It was just building a whole new facility, and it wanted to incorporate cog neuro into it. They asked if I'd come back and do it after the Davis thing. I had finished at Davis. I hired 10 people in four years, and the new Center was purring along. It's a great department now. I'm very proud of my contribution. So, I went back to Dartmouth and that became another Cognitive Neuroscience Center that we built up. Then I went on there to an administrative job— there was a sense of gratitude on my part in the sense that they needed a new dean of the faculty. I said, "Well, I'll put my name into the hat for that." The big surprise was they appointed me.

ZIERLER: [laughs]

GAZZANIGA: I learned then that I'm not cut out for those kinds of things. When you spend all your life dealing with people who want to get something done, they're rational, they're all scientifically based, "Yeah, we can do that," you operate a certain way. It may take you a few minutes, but you get the plan together, and you get back to work. When you introduce yourself to a broader range of thought processes and academic life, where that kind of thinking is slower [laughs], you realize that, oh boy, there are a lot of frustrations in a job like this. I was happy to have those days end and that's when I came out to Santa Barbara.

ZIERLER: Mike, back to the research. In 1989, you wrote a paper for Science—Organization of the human brain. What did you mean by "organization" and how did it differ from anatomy?

GAZZANIGA: I argued for parallel modularized systems and areas of specialization throughout the brain, distributed in different places. I call it organization of the behavior. What I stumbled upon, a lot of it by the split-brain work, of course, is that these things are sometimes not duplicated in each hemisphere. Sometimes they're only represented in one hemisphere. I wanted to tell that story, and it's a story that continues to have to be told because there are new problems, there are new issues that have to be understood with that view.

In a lot of recent work with modern brain imaging, you take a normal person, put them in a scanner, and present, say, a language task. Under the classic views, only the left hemisphere should show special activation with the new technologies. But instead, you now usually get a bilateral activation. If you were a Martian coming down to Earth and only looking at the modern brain imaging data, you would have a different theory about how the brain is organized. Whereas if you were a Martian 20 years ago, coming down, you would only have the focal lesion data. A lesion in the left hemisphere really disrupts language, and a lesion in the right doesn't. But it does do subtle things. How this all works requires some nuance and subtleties that haven't been fully articulated yet. Like everything else, you keep looking deeper, and there's other issues going on. Your theory will stand or fall, or it has to be incorporated in a way that it makes sense. As I just mentioned, I think with this new Lichtman study that just came out—people are going to have to think, what does that really mean for how we're going to build a theory about things like information storage? It's getting more complex. It's not getting less complex.

ZIERLER: That's a function of just learning more and just seeing how deep everything goes?

GAZZANIGA: Yeah. There was one today that caught my eye. You know the whole ChatGPT story now? They want to figure out how ChatGPT is doing what it does, because they don't understand how these things work with these big language models and how the computer's doing it. It's a mystery. They want to put that in a brain scanner. Wait a minute! That's what we're supposed to be doing with the human brain. You want to do this with an artifact? You've built it. You know every part—and you can't figure out what it is, and so you need something to come in and measure it? That was the quick headline. We're in new territory, David. We're in new territory.

While I don't quite know how it's going to play out, the people studying these questions are going to have to come with a new set of skills and knowledge, a new kind of cognitive stance. If you take people—take Caltech as an example—you've got people in dynamical systems and control theory and that's a hugely important thing for involving themselves in the study of the brain. But now you have people coming up through math and other systems that also want to be part of it. They have larger—they have interesting models in computer science and so forth. It used to be much simpler, say, pithing a frog and seeing its leg jerk out. That is how you used to study how the brain works. Oh no. You've got to have a lot deeper, more sophisticated technologies and skills to push this question forward, I think.

Blindsight and the Visual Cortex

ZIERLER: Mike, I wonder if you could explain the concept of blindsight, and why you spent some time looking at it.

GAZZANIGA: Blindsight is a term that was coined in the early 70s to describe when people with visual field defects, resulting from damage to the visual cortex, respond to visual stimuli that they do not consciously see. It was suggested that some type of visual processing was happening subcortically. Obviously, it is important in the visual sciences to know where visual processing occurs and to suggest that some of it is going on in places other than the visual cortex, and furthermore, not in the cortex at all, is attention grabbing. When you're in the clinic, however, you frequently see people with occipital lobe lesions, resulting in big visual field deficits. To test them, first, you put visual stimuli in the resulting scotoma, that is, the blind spot, where the hole in their visual field is because of the lesion. When we did that, we never had much luck showing they saw anything.

So, while I was at Cornell I became a bit of a skeptic. I thought it wasn't due to what people thought it was due to. Then a couple of students came, along with another colleague who was a very good psychophysicist. We said, well, let's see if we can study one of these patients in detail. We made a big effort to figure out another explanation for that body of work, and it was run by some very talented people. We found a patient who had a big field cut and studied what kind of information he could process. We built various kinds of eye-tracking devices, various kinds of visual and analytic devices; sometimes evoked potentials were involved. It was a very intense body of work on a point fundamental to the visual sciences: Where in the brain does the information get processed? When is it consciously processed, and when is it unconsciously processed? That's what we were after.

Basically, to make a long story short, because of the eye-tracking technology we now had, very specific, really, one-of-a-kind tracking, we found an area within the scotoma that could process information. Inside the scotoma – the part of the visual field that's empty because of the lesion – there was, nonetheless, a very small part that could recognize whether light had been presented or not—but all around it, nothing. Each patient's going to be different, of course, because each lesion is different. You have to map how the stroke actually affected the visual cortex cells in each person. So, what we were suggesting was when there is capacity, it's probably due to spared occipital cells and not some other imagined mechanism through other brain areas. All the occipital cells just hadn't been killed, and we could detect that because of the nature of the perimetry we were able to do with our machine. That just became a proposal to put on the table as to what the underlying mechanism is when you get these kinds of blindsight phenomena.

ZIERLER: Mike, tell me about when you got interested during the mid-1990s in the concept of neurocircuitry and if you started to think about the connections between the brain and electrical engineering, or this new field of neuromorphology.

GAZZANIGA: I'm not sure that—I don't know exactly what you're referring to there. Give me another—

ZIERLER: You wrote on neural circuits in cognition.

GAZZANIGA: Neural circuits in cognition is a general term used to try and capture whether you are getting closer to figuring out pathways that are involved in a specific cognitive act. Among things you might find is that there are different specializations combining in some way to allow a cognitive act, and you learn the connections between those two specialized capacities that allow for the common cognitive act. Neural circuits in cognition would be a way of saying that. It could also be realized through a split-brain kind of experiment, where there are partial connections, and some things could be allowed and some couldn't.

Could you demonstrate how specific a particular set of fibers might be contributing? Could you figure that out? In one study, we broke things down along that way on a language task. You're always motivated. I mean, your goal is to figure out more specificity, more specificity of function associated with specific neural pathways. Coming out of—I would say, maybe why I use that terminology, and maybe why you're getting into this—coming out of Roger's lab, that was where he lived was neurocircuitry: neural specificity, and how circuits grew and got hooked up and became permanent. The idea of neurocircuitry was something that was part of our training to always be looking for. He was using that term more frequently in animal models, but we took it into the human, and maybe that's why I use it a lot. Yeah, I would say that.

ZIERLER: I'm curious, coming from a Caltech perspective, somebody like Carver Mead, were you following what they were doing at the time?

GAZZANIGA: Yeah, Carver Mead and, the person I mentioned earlier, Gary Lynch, were colleagues. They had synaptic models and circuits exactly at the animals' more cellular level.

Yes, they were big scientific buddies working on that. Mead and their work came up at that Moorea meeting I was talking about.

ZIERLER: We talked—

GAZZANIGA: He was one of the early people—Mead was—to really get on that story.

ZIERLER: We talked about the Cognitive Neuroscience Institute. Tell me about founding the Society in 1993.

GAZZANIGA: [laughs] One thing leads to another. I was at Davis then, and it came down to: should we have a society? Everybody was talking this stuff up. We took a trip into San Francisco, which is right close by. Everybody wants to go to San Francisco, or used to. I went to the Fairmont Hotel and met with the events lady, and she told me how it would work. I said, "What would I have to do?" She says, "Pick a date, and we'll see if we're available." I picked a date, and she says, "You want to do it?" I talked to my friend who was with me. "Should we do this?" [laughs] "Yeah, let's do it." I gave my credit card and—I forget—a $3,000 or $5,000 deposit I had to make. We set it up, and 400 people showed up within a few months of when we decided we should do it. It kicked off the Society. People came with enthusiasm, and then the thing grew. The last one just finished four weeks or so ago in Toronto.

There were 1,500 people there and major presentations were given. It was a great event. I actually didn't go to that one, I couldn't. But I'm told it was a huge success, so we're happy about that. But what happens, in that too, my colleague Ron Mangun, who's now the head of the Mind Institute at Davis, also runs the cog neuro society. He's the current president. And lots of others who have been there from the start such as Patti Reuter-Lorenz, Marta Kutas, Dan Schacter and many, many others over the years. We try to run all these things by letting the energy of the members express itself without a lot of paperwork. Everything, all you think of is paper, paper, paper. How do you get something done without people having to spend their time on all the paper? That organization has grown, and Ron has been running it for the last few years—a bunch of years, actually—and he's done a fabulous job. He managed to run it through COVID on a joint meeting in San Francisco and a hybrid through Zoom. It was flawless, and I don't know how he did it. So that continues. What's going to happen in the not-too-distant future is we're going to turn over the Journal of Cognitive Neuroscience to the Society, so it becomes a unit together. There will be new leadership happening at any time now. The old dogs are getting older, and the young dogs are barking at the gate, so [laughs] you've got to let them in.

ZIERLER: Mike, returning to Dartmouth, this time for the college, not the medical school, just a general question. How much does that impact your research, being in more of an academic environment versus a clinical environment?

GAZZANIGA: Definitely, it brings with it that experimental psychologists are who you're bumping into in the hallways. They have the clever paradigms, and they always have some kind of cognitive or perceptual model to test. Also at Dartmouth, I was successful in recruiting one of the best brain imagers in the business. The psych department there in their new building was the first psych department to have a scanner. We had a 3T scanner in the basement at Dartmouth College, and Scott Grafton was recruited from Emory to come up and build and run the new Center. He's one of the top scientists in the field of brain imaging, originally trained at UCLA. He's a neurologist, too, in a psych department. That's another example, by the way of how the field of cognitive neuroscience draws on many different disciplines. You see a lot of that. The Berkeley group has two neurologists as their top cognitive people in their psych department, professors of psychology.

These barriers are miscible with new interests and new capacities. But, anyway, the Dartmouth faculty completely became interested, and one of the new things that sprang out of there was the field of social neuroscience. The social psychologists said, well, we want to know about mechanisms too. The fact of the matter is that you and I think about social process all the time. We're constantly evaluating others' intentions and morals, whole affiliations, you name it, in a social context. These psychologists have cleverly thought of paradigms that tap into those kinds of social realities. Then let's go look at the brain mechanisms involved. Now it's a vast enterprise, and one of the places it grew out of was Dartmouth. Also, it started up big in Ohio. Now it's all over the place. Again, who do you bump into in the hallway? "Hey, that social problem is a similar problem to what I'm working on in perception." People get going, and then things start to happen. It all works when there's a collegial atmosphere.

Drugs and Neuroethics

ZIERLER: Mike, I can't help but ask, in 2005, you wrote an article, Smarter on Drugs. Which drugs, and how'd you get smarter?

GAZZANIGA: In 2002, I was—let me think here for a second. In 2002—I guess I was thinking of the origin—I was invited to be a part of the Bioethics Council, President George Bush's Bioethics Council. This is when all of the huge questions were coming up about cloning and biomedical cloning and the ethics involved. Bush pulled together 18 people for this council, and I was asked to be one of them. They were people from all sorts of disciplines and moral beliefs, believers, nonbelievers. The embryo question came up. Then as we evolved—I stayed on the committee for eight years or so—we started looking at things like nootropics, which are drugs that are supposed to make you smart. What's the ethics of that? You name it, we studied it from an ethical point of view. It all wound up by my writing a little book called The Ethical Brain, where I was trying to pull in the discussion of ethics to a neuroscience setting in terms of things like, what do we know about the brain aspect of a problem? The Smarter Drug article was, I think, one of those articles. You catch me off guard here a little bit. I forget [laughs] which one was which. But that was the general context of that time. It was a fascinating experience for me. I tended to be part of a minority on the Council. About five of us on the committee were scientists talking about these issues. Others were looking at them from different perspectives, more traditional moral belief systems. But we studied, I mean, had to go through all kinds of issues: the nature of the embryo; the smart drugs; genetic, pre-genetic diagnosis; free will. You name it, we had to examine it, and it was a very fascinating experience.

ZIERLER: What was your entrée in thinking about some of the legal implications of cognitive neuroscience?

GAZZANIGA: That happened towards the end of 2000, around 2007. The MacArthur Foundation asked me to head up a program—Neuroscience and the Law—and it was a mixture of neuroscientists and lawyers. Most of the lawyers were, in fact, professors of law, and many of them were also judges. The program came about because Robert Sapolsky, whose name you might know—

ZIERLER: Of course!

GAZZANIGA: He had written to the MacArthur Foundation or suggested to them ideas. They were looking for ideas of things to fund. He suggested that the whole justice system needed to be revamped because of what we know about neuroscience. They took that suggestion and held a meeting in New York. They recruited Art Singer, former President of the Sloan Foundation, to examine the idea. Five or six of us had a couple of meetings, I think. Anyway, the one I remember was in New York because I had to leave the room and go to the bathroom or something. I came back, and they looked at me and Art said, "We just appointed you [laughs] the chairman of this new committee where we're going to do this neuroscience and law thing." [laughs] You get punished when you leave the room, I can tell you that.

ZIERLER: [laughs]

ZIERLER: Mike, tell me about being appointed to President George W. Bush's Council on Bioethics.

GAZZANIGA: The bioethics thing was a total call out of the blue. It turns out one of the members who had been appointed—the chairman of the committee was Leon Kass. He is a very well-known ethicist and physician from the University of Chicago and their social society program. A very smart man, very active, very conservative. He had talked to one of the psychiatrists on the emerging committee, Paul McHugh, who said, "We need a neuro guy." So Kass called me, out of the blue. I said, "Hey I don't know anything about bioethics." I'll never forget Leon Kass's statement to me. He said, "This is about bioethics. It's not by bioethicists. People from these various fields are going to be looking together at these bioethical questions." It was an intense time because everybody was hot and bothered about cloning and whether we should allow it. Everybody agreed: human cloning, no; but biomedical cloning, yes. That meant that you could study blastocysts up to some cutoff period, study them in experimental labs, and make stem cells and all kinds of good stuff. So, it was a hot topic.

ZIERLER: What about stem cells? That was also a hot topic then.

GAZZANIGA: Yeah. It was all part of that story.

ZIERLER: What was the commitment? How often would you go to Washington, and what kinds of things would you discuss?

GAZZANIGA: It was every six weeks. I think maybe there were six, seven meetings a year. I would go down on an afternoon and there'd be a full meeting the next day, then usually a group dinner, a meeting until the early afternoon on the following day, and then I could get home that night. Usually held in Washington, sometimes they were held at other sites. Francis Fukuyama was on the committee. Paul McHugh, the head of psychiatry at Hopkins, was the psychiatrist. Dan Foster from UT Southwestern, Elizabeth Blackburn from UCSF, Janet Rowley from University of Chicago and James Q Wilson from Harvard. I need a list in front of me to think of them all, you know, a long time ago. It's one of these situations where everybody's smart and everybody was articulate in expressing their view, but most moved from a different set of assumptions. How do we make progress here?

ZIERLER: Did you ever meet the President? Did you have a sense of his interest in bioethics?

GAZZANIGA: Yeah! We had one session at the White House. We went over, and we met in the—I guess it's the Roosevelt Room. Is that the room right off of the Oval Office? We were all in there, and Bush came in. He went around and met us all individually, thanked us for our service, and all that kind of thing. The council's activities were hugely covered by the press, especially the first part when we were dealing with biomedical cloning and the stem cell issue. Lots of coverage and the rooms were packed with observers and the press. It was quite a scene, actually.

ZIERLER: Mike, this might be a difficult question, but your service coincided of course with the height of the so-called war on terror, and the controversy over what was colloquially called "enhanced interrogation techniques," and what was called by its critics as "torture," which included psychological torture. Did the Council on Bioethics ever touch those kinds of issues?

GAZZANIGA: Not that I remember. There were plenty of things to talk about, and I don't think that ever made it. The first four years were run by Kass, and he kept pretty much to the biologic issues of the day. The second four years were directed by Ed Pellegrino from Georgetown University. I don't remember that coming up as an issue. It was a perfectly legitimate issue, although this was supposedly the scientific issues: What could go into the lab, what couldn't go into the lab, what transgressions were possibly being made on human dignity by doing certain kinds of experiments or not? Then always lurking in behind it all is the life question of the embryo. So pre-genetic diagnosis, you find out your kid is going to be X and Y, and you say, "I don't want that one." To a lot of people, that's a big problem. To other people, of course, you get another one. That, of course, sets the stage for all kinds of conversations.

ZIERLER: Mike, were you following the interrogation controversy? Were you aware that the CIA was contracting with psychiatrists?

GAZZANIGA: No, but I'm not surprised by that. Why wasn't I following that? Certainly, the waterboarding, I mean, fully aware at the level of a PBS listener, that kind of thing. But I don't remember that we ever tackled that.

ZIERLER: But that was just an agenda item issue? That was not any sort of suppression from the administration or anything like that?

GAZZANIGA: No, not that I knew about it. Anybody could bring up anything. It was very open, in that sense. There were five or six of us who grouped together on things, kind of scientifically based people. But the others were all admirable people. One of them, Mary Ann Glendon, I remember, was a professor of law at Harvard, and she was very conservative. She was an advisor to the Pope. But she was absolutely brilliant and hilarious. She had such a large view of the world. Even though she was very clear about the issues that you might think the church might be interested in, if you were a stick in the mud about stuff [laughs], that didn't fly.

ZIERLER: [laughs]

GAZZANIGA: Wonderful lady. Wonderful lady.

ZIERLER: Mike, when you were elected president of the American Psychological Society in 2004, was that more of an honorific or was that a heavy lift administratively?

GAZZANIGA: No, that was more honorific. There was a wonderful guy who made his career out of building that organization, Alan Kraut. I don't know if you ever came across him. Very skilled. He was a psychologist, a PhD, and he built the whole organization with just a firm hand, and humor, and skill. Really, hats off to him. What they would do is they would have these rotating presidents come in. You were elected, and so forth. But you held, I think, one or two meetings a year. You showed up, and you got to suggest the presidential lecture, a couple little things like that. But it was not an administrative hardship at all.

ZIERLER: Mike, writing The Ethical Brain—it came out in 2005—what kind of feedback did you get from colleagues about the notion of tackling such a difficult concept such as ethics?

GAZZANIGA: I think, by and large, friendly people. The explosion of interest in ethics in biomedicine and psychology is relatively recent. When people sit down and have to listen to an informed bioethicist talk about all the dimensions of what they had been taking for granted, they're interested. It's touching on all kinds of assumed beliefs they had, one way or the other. In general, I think they found it very illuminating. Out of that, that book helped in a way—you know who was big on it was William Safire.

ZIERLER: Oh!

GAZZANIGA: He was really the person that put energy into starting something called neuroethics. One of his jobs was running the Dana Foundation, and he mobilized them to fund programs in ethics and the like. He was the one that encouraged me to write the book on The Ethical Brain, on neuroethics. People found it interesting, and then I got to know people who actually were bioethicists. They were first-rate scholars, extremely thoughtful about long-term consequences of things and assumptions that were being made that may not be true in all kinds of social areas, and so forth. I think it was a positive experience. [laughs] One of my dad's quips comes to mind. It's probably not appropriate.

ZIERLER: Please!

GAZZANIGA: [laughs] My dad was a colorectal surgeon. He had a special view of the world. [laughs] I said to him once, ethics—we were talking about ethics. His line, "Ethics? That's for the other guy." [laughs]

ZIERLER: [laughs]

GAZZANIGA: One of the most ethical people I knew.

ZIERLER: That's great. [laughs]

GAZZANIGA: But he had a sense of humor. I think it's very important, and now it's a very active field in the academy. In psychology, if you go on one of these human subject review committees that have to approve research protocols at universities—oh my gosh—they worry about everything now because of the ethical dimensions of it. It's part of our life now. There are a bunch of famous ethicists. Hank Greely at Stanford is one of them. Emory has got a great program in ethics too—actually, many places do.

ZIERLER: Mike, in our next conversation, we'll pick up when you decide to move the operation to UC Santa Barbara. Last question for today. Was developing the SAGE Center for the Study of the Mind, was that what convinced you to go out to Santa Barbara?

GAZZANIGA: It didn't hurt, but it was thrown in at the end of the decision process because it just happened that they had received the funding for it. They said, "Sure! Why don't you run this too?" We were ready to leave Dartmouth. The kids had grown up. The person that hired me at UCSB knew I had a house in Santa Barbara [laughs], which I had built with my own two hands, some 30 or 40 years ago. They knew I would like to come back to it.

ZIERLER: Oh wow!

GAZZANIGA: They had a special hook. [laughs]

ZIERLER: You kept onto it all those years?

GAZZANIGA: Oh yeah!

ZIERLER: Oh wow!

GAZZANIGA: It allowed us to kind of, you know, Santa Barbara, as you know, is a little pricey town. It's actually Carpinteria where I live, which is right next door. It worked out well.

ZIERLER: Mike, on that note, we'll pick up next time in 2006. I want to hear all about the SAGE Center, also the MacArthur Law and Neuroscience project. We'll take the story from there, right up to the present.

[End of Recording]

ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It's Tuesday, June 11th, 2024. It's my great pleasure to be back once again with Professor Michael Gazzaniga.

Mike, as always, it's great to be with you. Thanks again for joining.

GAZZANIGA: It's great to be here too.

Launching the Sage Center

ZIERLER: Mike, we're going to pick up right in 2006, when you joined the faculty at UC Santa Barbara. First question, the SAGE Center for the Study of the Mind, were you the founding director, or does this proceed your tenure?

GAZZANIGA: I guess I was the founding director. It was a philanthropic gift that was simultaneously being acquired just as I was being hired. There was a mutual facilitation that I could do it if I took the job, that kind of thing. But it would've happened, I think, regardless. As it turned out, I was coming into this wonderful opportunity, and they said, "You'll run the SAGE Center as well."

ZIERLER: What is the word SAGE? What does it mean here? Who is or was SAGE? GAZZANIGA: It's a great name, but it actually refers to the SAGE Publishing Company. ZIERLER: Oh, I see. [laughs]

GAZZANIGA: They were the benefactors. The owners, the couple owner of SAGE were Sarah and George, so they contracted it to SAGE, and that's how they got their name. They've had great success, as you know, as an academic publishing house. Sarah, the surviving spouse, for a number of years has been an enormously important philanthropist, especially to UCSB and the whole Santa Barbara community.

ZIERLER: Now, how much leeway did you have for putting your own imprint on the SAGE Center's mission? Was that sort of preformed, or did you have opportunity to make it what you wanted?

GAZZANIGA: What I've discovered, when you're in one of these situations where you're leading an academic group, if there aren't personal animosities between anybody for some reason that's unimportant to anything, people pretty much say, "Go ahead, take the lead. When you screw up, we'll tell you." Therefore, it cuts down on a lot of back and forth, and endless meetings about details that don't amount to anything in the end. I can say, both when I was at Davis getting their Neuroscience Center off the ground, and here at Santa Barbara, that I've had a wonderful relationship with the faculty. Santa Barbara is prone, almost its definitional self, to be interdisciplinary and to call upon many different departments to come together in coherent projects. There's not a sense of foreignness to that idea. It was easy to jump in and then just try to do it. Now, to do it right is hard work. Everybody wants to retract back to their specialty.

That's just what we do. We know how to do this, we don't know how to do that, but we know we've got to start doing that because that's where the cutting edge is. To pull it off, you need to not only bring in the right speakers, have the right sort of social setting at the institution, but then there's a lot of social activity that's got to go with it, with getting people together.

A big part of our SAGE Center here that's actually become quite well known is, when we bring a guest in, not only are there the usual meetings with the faculty and the students, but we always arrange a private dinner party where, after the food was served, there would be the big question. It was time to put the speaker on the hot seat. "What do you mean when you say X, Y, and Z?

How can that possibly be true?"—kind of thing. It's all done in high, positive spirits, but it's also asking, "What's really going on with this topic?"—that kind of question. That's turned out to be the best part of it, because people really will talk in that kind of setting. We have our local faculty who are the best in their areas—whomever the speaker is—and it has become an aspect of academic interaction. I'm told, time and time again, it was really unique and very positive, very constructive. All that's a long-winded way of saying that just to set up a program by design, and say you want to do stuff, that's the simple part. The hard part is to actually get it to go. I can tell you about one dinner. I won't mention who the people were because I wouldn't want to embarrass them. But at one of these dinners, it turned out that two of our speakers were in town at the same time, so we combined the dinner, and both of them were there. One was a major philosopher, and one was a major neuroscientist. As we were getting going on dinner, we couldn't wait to get to the entrée. These guys wanted to talk. One of them leans over across the table to the other, and says, "Now, so-and-so, you don't actually believe that bullshit you're telling us, right?"

ZIERLER: [laughs]

GAZZANIGA: Everybody goes, "Whoa!" Then, everybody cracks up laughing. But the question was serious. Then this intricate conversation ensued that broke the ice. That's the kind of question that was on everybody's mind. I think the neuroscientist was proposing a very complex thing. "Do you really think that's how it works?" But it's so hard to get those kinds of conversations going and to get real interdisciplinary activity, and it's just hard work. It shouldn't be in any other category. It is not going out and having a few beers with your friends. That's not it. It's, this is what we do here, and there's going to be a very intense conversation at this point of the dinner as to what is the field doing and what are we doing. I think that, well, I've said enough.

ZIERLER: Mike, is your sense, was there an interdisciplinary research culture centering around the mind prior to the SAGE Center, or the SAGE Center really corralled all of those siloed interests?

GAZZANIGA: No, not at this campus, anyway. That was why it was such an important thing to do on this campus. UC Santa Barbara is reeking with talent from all kinds of biological and physical sciences as well as a great engineering school. It's a very scientific campus. From the start, we involved lots of biologists, physicists, economists. While the SAGE Center is based out of the psychology department, that's only for purposes of accounting for the dean. The notion behind it is to try to bring together departments who are interested in the study of the mind.

ZIERLER: What were some of the pleasant surprises for you, given how diverse all of the academic affiliations connected with the SAGE Center were? It wasn't just biology and physics; it was humanities, it was economics, it was philosophy. What were some of the most surprising disciplines to you that had interesting things to say about the mind?

GAZZANIGA: When you go into the humanities, you will always get people interested in the idea of ‘what do we know about the mind,' obviously. They're humanists. They want to know what is this thing, and how do we think about it, and what's unique about it? Then the skill is to find ones that have actually thought about it and have some understanding of scientific process, vocabulary, and the rest. We had such people here on campus. Again, the work part of it is: Who exactly are these people? We don't want to have to go rediscover everybody. There's knowledge existing about people who have that kind of aspect to their intellectual life. We picked up on those people. Then it was quite surprising, the number of physicists that wanted in—Santa Barbara is well-known for its physics efforts. It's got six Nobel Laureates, and all the rest of it.

They were totally engaged and helped us with our effort, even though they have quite a major effort of their own on a broad base of questions at the Kavli Institute. But they were very helpful and, of course, the biology department was all in. Then I brought in the economics department, and recently, we've been able to be more active with the philosophy department. There's lots of people involved. What do we do? We try to have a cross-section of speakers. We had two programs initially, where people came and stayed for two or three weeks. Then we had the shorter version, where they came for two or three days. You have to plan these things in advance because of the time, everybody's busy. For one of the programs, we finally rented an apartment in town that became the SAGE apartment, and people could use it at will. Sometimes people called up, and said, "I'd like to come out for two or three days." They would come on their own dime, as it were, and we'd let them stay in the apartment—all those little factors that just encourage being together and thinking about the problems. The well-known philosopher Dan Dennett was a big friend of the Center, and he came several times to just be part of the culture here. People like Steven Pinker and Rebecca Goldstein and the generalists just saw what it could do and would do and were very supportive.

ZIERLER: What impact did this have on your own research, being in such an interdisciplinary environment?

GAZZANIGA: When I took the job, I was 66 years old. So I had, for 40 years, been running labs and postdocs and grad students, the whole nine yards. What you don't think of, as you age into your 60s, is that to take on a student, a new student in your early 60s, is a dangerous game because you don't know how long you're going to be having an active lab. A lab is a very complex thing and your commitments to people may go beyond your plan to be at the university. This opportunity hit me at a time when I was winding down my lab, which was fine. But I wanted to wind up these intellectual programs and have the fun of nucleating idea groups— which we did and have done. It becomes a different kind of thing you do, for sure. I wrote a number of books during this period, too, which allows you time for that. It's a different game. But I want to emphasize—we've had 70–80 people through here in the last few years, each one of them is really tops in their field. It's a whole experience to manage all that, which is really great. But, again, I have to emphasize that it's work to get interdisciplinary things to work. It doesn't just happen. I suppose, ultimately, in the room as they say, in the room where it happens, the penny drops, and people say, "Wait a minute! That person really has an idea there that I should be applying to my field." There's that wonderful event that occurs where somebody's perspective actually changes. We just had one of those experiences last year. It makes it all worthwhile when you have successfully put together, into the same space, people who didn't think the same way, and come out saying, "I've been missing something here."

The thing that came out recently that I put together just as I was retiring this past year, a spin-off, as it were, from SAGE, is something we called The Foundations Institute. It's to bring small groups of scientists together—five, six people from multiple disciplines to talk about ideas – mainstream scientific ideas that folks take seriously – that maybe should be junked, that just don't work anymore or which never really worked in the first place. The point is to address head- on how scientific dogma captures people and keeps them in ruts. Take a particular question and reexamine it. It's so hard to liberate oneself from your field – what you've been taught, what your classmates all know in the immediate sense, what your colleagues are promoting, what they think is important. These things and beliefs and findings are real; they're all important things.

But does the dogma shut down the next level of thinking for too long a period of time Scientists get caught in these stories. In any field, the stories are pushed hard, and they're established through graduate students and postdocs and fundings. Pretty soon, an idea gets set, and it's hard to have a variation on that idea because of all the natural forces that contribute to how the science bureaucracy works. We're all aware of this. We don't like to think about it. This idea was, well, come on, we're all grown-ups here. Let's take some dogmas and get in a room where there are no rules, and everybody has frank discussions about, well, what do we really mean by this? How could this be true? Are we at a dead end on this method or not? Do we have to have a new question over here or not? This approach is not getting us anywhere, what else could we try? You know, all those kinds of questions that are hard to ask. They're hard to ask because people have a big investment of time and work and funding in their points of view as they go into this. They spend their career on one dimension of a problem, and they've developed it, and it is good science. But we've got to get to the next level. Just because this works doesn't mean it's the right way or the only way. There could be other interpretations—and so forth. This is common across all scientific disciplines. This is a big issue.

Quite frequently, the king dogma maker of whatever the topic is, is the very person who frequently has the greatest doubts about it. But it's not good business for them to be saying that, and so you want to be in a room where there's a high respect and mutual value between people, and they have a full discussion about it and challenge it. We had one of these, about six years ago, which produced the seed of the idea for the Foundations Institute, on the importance of the synapse and memory storage of the brain. A fundamental question, everybody had been studying it for years, and somebody was challenging that that's the way we should be thinking about it.

This meeting goes usually for two days, a couple days, maybe two and a half. Everybody said it was the best meeting they had ever been to, because there was just the, "Okay, we're really going to talk about this. We're not doing a slide salad kind of thing, where everybody just presents slides, tells their story and goes home. No! We're starting here. Everybody knows everybody's work here. Let's just start talking about the question and have a real full discussion about it." It's, again, work. It takes work to get it going. You've got to make sure that you haven't stumbled into inviting someone who's just a naysayer. There are people like that in the business, of course. For these special meetings to work you want people who have a point of view, have a strong point of view, but they're open-minded and smart and not afraid of discussing an idea. All that takes work, judgment. When it works, it's great. Sometimes it doesn't work so great. We've run two or three meetings, and it's now up and running—I've retired out, but another one comes up next week.

The Pleasures of Interdisciplinarity

ZIERLER: If I can broaden the question out, what has been the impact on split-brain research generally from having this interdisciplinary perspective?

GAZZANIGA: I guess, for me, by having this broad-based program, we are quick to invite people who have ideas on how the brain enables conscious experience. We had, over the years, a large range of people—and this goes all the way from people with a computer science background and network science kind of backgrounds, to neurologists who see variations of things in the clinic that are interesting, to the molecular and cellular people, and also to linguists, anthropologists, philosophers and authors, literary types. You learn how those people are looking at the problem. For me the takeaway is how I have more work to do on communicating the take- home lessons of split-brain research. As I mentioned this back earlier, I'm starting a book where I try to do that—

ZIERLER: Wow!

GAZZANIGA: —and I won't tell you what it is. [laughs]

ZIERLER: Okay. [laughs] Mike, the other significant affiliation I wanted to talk to you about when you got to UC Santa Barbara, the MacArthur Foundation's Research Network on Law and Neuroscience, did that also start at this same time or is there a pre-history there?

GAZZANIGA: The MacArthur Law and Neuroscience project popped in to us around 2007. We arrived here about 2006. It came in, for us, out of the blue. But I was recently asked to talk about the history of that. I think what happened was that after my six-year experience being on the President's Bioethics Council, people said, "This guy can work with a larger group of people, a committee, looking at bioethical questions, and because he can do that, maybe he can help."

I'm thinking this is how the MacArthur Foundation was thinking about it. They wanted to start a project on neuroscience and the law, and that came out of their solicitation of ideas from all their fellows. As I have already mentioned, one of the people that answered their call and wrote a proposal was the neuroscientist Robert Sapolsky. He felt there was a lot going on in neuroscience that may address how we think of punishment and what is a proper punishment in this modern age. MacArthur bought that general concern from Sapolsky, and then they started looking around for how they would start one of their networks.

We did that for three or four years, looking at all aspects of the question, could you use neuroscience to make better predictions of parole? Could you use neuroscience to help the justices in the mitigation of a crime? Could you use neuroscience as evidence that the person was or wasn't responsible for what they did? A host of questions, and so the task was to bring together lawyers, neuroscientists, and judges to start thinking about this—and, as I said, we did.

But it was a real challenging thing. Lots of heated discussions about where neuroscience could help, where it couldn't help, the nature of how law and the legal system thinks of things. I'll give you an example. Take the role of the expert witness, perhaps a social scientist relating all kinds of statistical outcomes. Let's say it's a parole hearing. He says, "There's a 55 percent chance this person is going to recidivate if you parole him." People say, "Okay. All right." Then let's imagine that the expert witness is a neuroscientist and now she increases her prediction to an 85 percent chance because of all the things we know about this guy. So together, with neuroscience and behavioral cognitive science, we pretty much know what this guy's going to do if you parole him. Okay. Now, the judge, who is in the hot seat, has to decide whether to grant parole or not. What the judge is weighing is an 85 per cent chance of recidivism versus only a 15 percent chance that things will go well, plus the law allows the judge to consider mitigating circumstances, both positive and negative ones. Should the judge give this guy, this particular case, the 15 percent chance or not? The notion that neuroscience is tightening a particular probability is true. I mean, that's all good. But how confident are you neuro guys that you're going to raise your predictions that high anyway? Down at the 50 percent level, there's all kinds of decisions that go into paroling a guy or not, will increasing the probability of the predictions change any of that? Just stuff like that, it was one after another, a story like that. We didn't know how the legal system worked.

Give you another one. What goes on at the courthouse, the day-to-day maintenance of law? Are people down there looking at making these intricate legal arguments? No! It's administrative.

Somebody's been charged with a crime and may be assigned a public defender. The public defender's trying to decide whether there's enough money in his budget to give the guy a brain scan or enough to do X, Y, or Z. Then scheduling a date. Then there's bail. It's all this administration. The notion that justice is being the thing that comes out of that courthouse, it's just not reality-based. I mean, ultimately, there's the decision, of course. But the process and procedures of bringing someone or something to an actual decision has all this complexity.

The thing that was so interesting in the first year or two was that the professional fields really had no idea how the other field worked. Neuroscientists didn't really know how the legal system worked, and the law professors and the litigators and the justices really didn't know how neuroscience worked. We didn't know how the judicial part of the system worked, namely that when it actually comes to meting out justice and punishment, it's up to the judge. That's who does it. That became the most fascinating part of the story for me because that's where the rubber's going to hit the road, where you can make an argument that you have evidence that should mitigate the set punishment of something for somebody who did something. That's really tough, hard work to do all that. Anyway, we all finally learned how the others play their game, what their professional responsibility was, how the actual justice system works as opposed to how we think it works from Perry Mason and all the rest of it. That became a lot of self- knowledge, self-learning there.

That particular project changed into really trying to establish a formality for how lawyers were going to deal with neuroscience. The project was passed on to a lawyer, Owen Jones from Vanderbilt, and he took over running it at that point. That was about 2010–11, somewhere back in there. Then it kind of changes its goal to really being specific for how this whole new science was going to be used in the courtroom, and they put out a couple publications on it.

ZIERLER: Does this Center suggest a new interest in the law in neuroscience?

GAZZANIGA: It turns out, how science was used in the courts was very interesting. If you hadn't thought about it before [laughs], you found out how interesting it was. Up until the 1950s, 1960s, what was called science was a psychiatric, psychoanalytic evaluation of somebody. Those psychiatrists, psychoanalysts were brought into the court as the expert, and they would say that was the hard science. Then all of a sudden, it wasn't. All of a sudden, the expert is transformed into some guy with a brain-imaging machine that's telling you about spots in the brain and what the implications of that are. That's just a totally different game. By that time, of course, psychoanalysis and that kind of thing was defending itself as to whether it really was a science or something else. There had always been interest in trying to figure out the cause of crime. It used to be psychiatry held reign there. Now it's just a different story. But there are serious arguments that it is too soon for neuroscience. I kind of side with that, that there's too many ways you can explain yourself around a neuroscience finding to make it definitive at this point. I think neuroscience is going to get there, I think it's going to be hugely important, but I think it's still a number of years away.

ZIERLER: Despite it being too soon, do we see practical impacts on a neuroscientific perspective on legal matters in courtroom procedure, in sentencing, in probation? What are those impacts?

GAZZANIGA: You mentioned all the things that I think it will have an impact on someday. But we aren't there today. I mean, to make a simple point, one of the favorite defenses is of someone who engaged in violent behavior and then turns out to have left frontal lobe damage for whatever reasons. Then the story starts, well, people with left frontal lobe lesions can become disinhibited and carry out a violent act. That's all true. The problem is that the frequency of violence in a normal population is about four percent. If you have a left frontal lobe lesion, it certainly increases. People argue that maybe it goes up to 11–15 percent. But that's [laughs] 85- 89% percent of people with lesions who don't engage in violent behavior. You get into the realization that all findings are going to be statistical probabilities and all the rest of it, and so is there room in the diagnosis to say, "Yeah, that happens sometimes, but it didn't happen in my case here"? So those kinds of issues. It's going to be complicated as we know more and more. I think it's very important. I believe it will be valuable at some point. But right now, I think it has limited utility. People think neuroscience is going to come in, you know, and that is that. Here's the period in the story. No! It is not there yet for that.

ZIERLER: Just to clarify, this is to say that we don't see these impacts yet? We don't see this already affecting all kinds of legal issues?

GAZZANIGA: No, not yet, in my opinion. I mean, you might get a different answer from somebody else, but I don't see it that way.

ZIERLER: What would be your response? I can imagine a critic saying that, "Once we factor in all of these issues, ultimately, it's going to lead to more leniency because we're coming up with biological excuses for illegal behavior."

GAZZANIGA: Or the other way around. The biological data might be viewed as suggesting a hopeless state of ill-will and evil. There is lots to be worked out.

ZIERLER: Now, is the MacArthur Foundation still supporting this program, or has it ended?

GAZZANIGA: I think it's ended, yeah.

ZIERLER: Has it ended more or less on the basis that it's too soon? Is that sort of the conclusion of the effort, that this is something perhaps to pick up at a later time?

GAZZANIGA: I think that is the view of many of people who worked on the problem, and others who didn't work on the problem but read about it. They think it's too soon. However, let me put a caveat on it. The way foundations work is they kick things off the ground and then if they click in terms of societal need, other agencies come in and underwrite their use. The foundation will then move on to another problem and try to kick that one off the ground.

Foundations aren't in the business of sustaining one of their efforts. They're interested in developing the argument, the need, make the society aware of it, and then go do another one [laughs]—which for those of us doing these things, leaves us saying "Wait a minute! [laughs] Come on! We just did all this work." But that's just how it works.

ZIERLER: To go back to this concept of, you know, maybe there's a permissiveness that might occur as a result of thinking about neuroscience, one article you wrote, My Brain Made Me Do It, just begs the fun counter to that. What else would make you do it, if not your brain?

GAZZANIGA: Right. [laughs] From that point of view, nothing, you know.

ZIERLER: [laughs]

GAZZANIGA: Got it. But my view on all this is, yeah, so then you get into these very complicated questions of free will and responsibility and so forth. The reductionists came in and said, "Look we know that the brain is what's ultimately responsible for everything that we're experiencing, so if you did a bad act, that's just your faulty brain, and blah, blah, blah." My answer to that is, "No! That's not fair. That's not right." How you have to think about it is, you want, what I phrase as, an automatic brain. When I want to point to my nose, I want my hand to go to my nose. I don't want it to go flying off in some other direction. I want this thing to work like a clock. That's great. Where do you put responsibility then? Actually, responsibility is—the way I see it—a social concept. The way to think about it is, if you're the only person on Earth, the idea of personal responsibility has no meaning. [laughs] Who are you being responsible to? Enter the second person. Now, wait a minute! Now there's two of us here. We're going to have to set some rules up here for how we're going to behave with respect to each other, because there's only one piece of pie over here, and there's two of us, so how are we going to work this out? Responsibility means you have to be responsible to the social group; those are the rules.

Whatever your brain state is, whatever your neurologic state is, you can learn rules. Most of your life, whoever you are, you're responding to rules. Do this. Stop at the red light. Don't stop at the green light. Do this; don't do that. You're following all those rules. Well, here's another rule you're supposed to follow, and you're not following it! Guess what? We're going to take you out of the grid here. You broke the rules of the game, and there's got to be accountability. If a node goes down in a computer program, it becomes somehow not functioning—boom!—get it out of the network. We can't have that. I just think there's a lot of confused thinking about what we're really talking about on these issues.

Assessing Human Uniqueness

ZIERLER: Mike, around this time, you also started to get interested in the concept of uniqueness. Not only are human brains unique, but is the uniqueness of human brains what makes humans unique? I wonder if you could explain both how you got interested in these ideas, and what some of your conclusions are.

GAZZANIGA: There was a hunch for—what is it in human brain organization that might not appear in the neuroscience or neurophysiology we understand of all animals with brains? I mean, here we have this big, incredible thing called a human being and all the incredible things it does. Does it process information in a way that may be unique and underlie a lot of our incredible abstracting abilities, language abilities, and all the rest of it? That has been the deep assumption of neuroscience – that human brains share certain features but have some unique ones. We're all made of neurons and neurons and neurons, and we can study squid and flies and rats and everything else. Those studies will inform and can be used to model how it must work in a human. Some people say, well, maybe there's a different neurophysiology associated with human cells. Maybe they're doing things that are different. Very few people have really gotten into that. One of them whose work I started to talk about a little bit was the very famous neurophysiologist, Gordon Shepherd at Yale. He started reporting that he could get human cells, which had to be excised during surgery for epilepsy, to grow in a dish, then observed if they responded in the same way as other neurons that he'd studied from other animals. He found some differences late in his life about it. He was trying to pursue that idea. Are there going to be differences in the way the underlying hardware works that we have to be alerted to for our models and our understanding about humans? That's one level. Then people looked for different ways. Are there different cortical features in particular parts of the human brain that you don't see in primate relatives? There've been various discoveries, claims along that route as well.

These are all just trying to look for—is there anything different that just would really enlighten us on how the brain may be processing new information versus other animals? I would say, it's a young enterprise, and we haven't quite gotten our hands on it. I wrote a book called Human. I just said, we've lost the thread. We lost it. Humans are pretty clever. We're doing all kinds of things we can't figure out, and so maybe we should just take an assessment of that. Then you're off to the races. For example, you could ask: Do all animals have a theory of mind? Humans have it, but do animals? Theory of mind is the innate ability to understand that others have desires, intentions, beliefs and mental states and the ability to form theories with some degree of accuracy about what those desires, intentions, beliefs and mental states are. I have a theory about you and you have one about me. It was an idea originally brought up and thought through by the psychologist David Premack. It now has become a huge field in cognitive neuroscience. All kinds of people are studying which brain mechanisms seem to be involved when you're thinking about others versus yourself. It gave a whole new framework to think about how the human brain may be organized around a lot of social concepts, instead of just plain old how we calculate, how we speak, and the sort of standard cognitive science questions. How do we calculate and anticipate and respond in a social setting? It's a big deal; lots of fascinating work going on in that area as well, too, including whether other social animals have it or aspects of it.

ZIERLER: It seems like the easier question, the more tractable question that you alluded to is, just anatomically and physiologically, are you convinced that the human brain is different than our primate relatives or not necessarily?

GAZZANIGA: Oh, there's tremendous commonality, of course. A couple months ago— the time flies here, the Lichtman paper that I mentioned earlier has received a lot of attention, as it should. Again, he's worked out the number of connections in—and get this—one cubic millimeter. One cubic millimeter of a human brain has something like 50,000 cells and 150 million synapses in one cubic millimeter. He wants to know every one of them. Then when you get done with that, well, you've still have a few more than one cubic millimeter to figure out. It's stupefying! Yet that's the complexity of the system. To start looking for differences doesn't seem to be, I mean, it seems to me to be a logical thing to do. But, first, you've got to establish the baselines, and you've got to establish what is routine and so forth, so a long way to go with that one.

ZIERLER: That was a bit of a non-answer. It seems like, for you, the more interesting one is not the physiological, the anatomical, but the responses, the things that make us different that you can measure in terms of behavior, perhaps.

GAZZANIGA: Oh, for sure! Now, sure, behavior is what we have.

ZIERLER: Mike, tell me about the question of so-called cognitive-enhancing drugs. Firstly, do you think that they exist? Is there a pill that you can take that enhances your cognition, and what does that even mean?

GAZZANIGA: This came up on the Bioethics Council, let me tell you, that was a big issue. Nootropics, they're called, N-O-O-T-R-O-P-I-C-S. The sense at the time—this goes back 2005, '04, '03, around there, and then later on followed up a few years later—the sense was that it was oversold, that we didn't know yet about a pill you could pop and, all of a sudden, you could understand quantum mechanics. [laughs] I'm not sure that pill will ever exist.

ZIERLER: [laughs]

GAZZANIGA: Of course, this is of intense interest, public interest, because of Alzheimer's and other diseases. When you start experiencing diminished cognition, is there something I could take to reverse this? Or the kid that wants to get a higher score on the SAT can pop this pill, so his light burns brighter during the test. All those kinds of medications that were discovered at that time turned out to be nothing more than attention-focusing medications, but nothing infusing the circuits to make them process information better. Now, whether there are new claims, I'm not up on that. But I think if there were, I'd know about them, so my guess is they still don't exist. They work around the edges. Again, they maybe help you focus your attention, maybe keeping you more alert, awake. Like coffee. This gets you to do the damn task and be there, present, and sustain your working system on it, in the time it takes to solve the problem. I think it's that kind of stuff; not enhancing the computational power of problem- solving, per se.

ZIERLER: By that, do you mean, for example, if it's well-established that a drug like Adderall can help people focus, is that not necessarily the same as cognitive enhancement, where there's a pill that would make you, quote, unquote, smarter?

GAZZANIGA: I'm talking out of both sides of my mouth here. If you have Adderall, and it helps you to focus, and we get more out of you, people commonly say it makes you smarter. But it actually didn't make you smarter. You were just as smart before, but you were just all over the map. It's putting constraints on your normal analytical abilities to get you to focus on the job. That's how I see it. It's not making you smarter. It's constraining your lack of interest in solving the problem at hand by making you focus on the issue, and then using what innate abilities you have to solve the problem. Does that make sense to you?

ZIERLER: It does, yeah.

ZIERLER: Mike, some of your retrospective writing, some of your autobiographical writing, you use the phrase or the term "two brains." Is that meaningfully distinct from split brains?

GAZZANIGA: I didn't hear that. I used the term, what?

ZIERLER: Two brains as opposed to split brain, I wonder what the distinction, if there is one, would be.

GAZZANIGA: It was basically saying the same thing with another phraseology. It wasn't anything different than what was always meant by split brain.

ZIERLER: Is there something even provocatively to think about split brain as, to some degree, not thinking we shouldn't think about the brain in unitary terms; that it is, to one degree or another, two brains?

GAZZANIGA: I always say that the split-brain results enable us to consider the question that there can be lots of local processing units solving problems that are unbeknownst to other processing units in the brain. It allowed us to entertain that concept. The reason we could do that was because the split brain was so robust a phenomenon that we knew what one side was working on and solving and how far down some cognitive path they were, and we knew the other side didn't know anything about it. Now, in that sense, the research on split brains is just a tool to get at that question. It enables people to realize there can be all kinds of parallel distributed systems going on in the brain, where one part doesn't know what the other one's doing, but somehow it gets pulled together into an overall coherence.

Split-brain research, I think, really emboldens that idea because we can demonstrate it for you. That's just the way it is. When you see a split-brain patient tested, it's flabbergasting. When you're in the room, you just don't believe it. Wait a minute! The left hand actually doesn't know that the right hand's holding an apple. What? How can that be? All from the simple little tests like that. To this day, it makes you sweat to see that coming out of this person you know extremely well, and who seems utterly normal in every other way—and is—except for when you ask the question in the way that the split-brain researchers know how to do it. You see that there's this total separation of information, and you show that truth.

The Free Will Conundrum

ZIERLER: Mike, in 2011, your book, Who's in Charge? Free Will, and the Science of the Brain, by necessity, did you have to become something of a philosopher to take on this topic?

GAZZANIGA: Oh yeah [laughs], boy. I must say, I was aided by a friend of mine, a colleague, the philosopher, Walter Sinnott-Armstrong, who's now at Duke. He helped me tremendously. I was asked to give the Gifford Lectures in Edinburgh. They are a well-established set of lectures usually given by philosophers, but also many a psychologist and others interested in the mind and its relationship to the deep questions of religion, and all the rest of it. When I was on the Bioethics Council, that group of 18 people, they all instantly knew about the Gifford Lectures—it was interesting—whether they were lawyers or doctors or theologians or ethicists.

When the invitation came to me to give them, I felt flattered, of course. It basically took two years of my life to prepare six lectures because I knew it was serious stuff, and this was going to be a wide-ranging audience—and it was indeed. When I delivered them in Edinburgh, it was probably two of the most intense weeks of my life. I gave three lectures a week to large crowds on topics that they wanted an in-depth report on--how neuropsychology, how cognitive neuroscience would view these kinds of things. The hosts wanted it to grow out of my split-brain work. For me it was a time to learn a lot of philosophy and to bring it into the experimental science story.

ZIERLER: Did you come into this project with well-formed ideas about whether free will exists?

GAZZANIGA: That issue certainly focused the mind, you know, having a coherency through six lectures, winding up on the free will question. That certainly was my moment to tell my story.

ZIERLER: How did your views on the topic change as a result of the book?

GAZZANIGA: It gave me an opportunity to think it through. Prior to that, you would say, you're an experimental scientist. You go give a talk. You tell them what you did, you show them the stuff, and you say, "Here's what I think it means," and you go home. In this kind of assignment, they want you to plug it into these larger questions of philosophy that people have thought about for hundreds of years. It's a different balance, a different kind of exhaustion occurs. But, yes, I think it brought order to my thoughts to be under that kind of gun.

ZIERLER: What special influence, you know, split-brain research, and the left hand not knowing what the right hand is doing, what special insight does the split brain have specifically on the question of free will? In other words, if one part of our brain is unaware of the other part of our brain, doesn't that, to some degree, blow up the idea that free will is a singular entity? Can it not be multiple entities?

GAZZANIGA: "How does it work? How does the brain work?" you're asking. Oh! I didn't tell you that part. [laughs]

ZIERLER: That's right. [laughs] You were getting there.

GAZZANIGA: You're asking all the right questions. Of course, the split-brain story, just to remind everybody, is saying, guess what? We can carry out a surgical procedure to help this person with epilepsy. Basically, they end up with two separated conscious systems, each capable of doing its own thing outside the realm of awareness of the other. Whoa! What'd you just say? Then you say it again. So, yes, if that's true, then there can be two systems all within one human cranium, with two different goals, and in conflict. Who wins that battle? Who is responsible?

Then you've got to start doing a bunch of experiments to try to sort that out—which we've done over the years. You certainly come away with a view that there are two different willful systems in the brain that can be working in concert or in conflict. [laughs] Did I tell you this one? I was in the elevator with George Miller at Rockefeller one day, the door opens and in strolls William Estes, this famous psychologist. George introduces him to me and says "Bill, Mike's the guy that does the split-brain research." And Bill quips, "Great! Now we have two things we don't understand."

ZIERLER: [laughs]

GAZZANIGA: It's kind of true. Of course, I'm pushing it even further. There are a gazillion little operating systems in the brain that are making decisions all day long that we're totally unaware of. Let's face it, 99 probably .9 percent (99.9%) of the stuff that's going on in your brain and my brain, we're not aware of. It's outside of consciousness and, yet, it's working, doing all this stuff all the time, day after day. How are you supposed to be consciously responsible for that? We're thinking about this in an awkward way. I don't think that helped.

Anyway, that's my story.

ZIERLER: If there are aspects of your writings on this topic that naturally lead to the conclusion that free will or at least part of free will is illusory, it's an illusion, I'm curious if you've ever engaged with religious organizations, who must insist that free will is real? It can't be an illusion, based on the idea that, you know, on what other basis would God judge us?

GAZZANIGA: That's the idea, all right. But think of it this way. Let's say you're as automatic as I maintain you are. You are a decision-making unit. That's what you are. What are we doing all day long? Making decisions, that's what we do. What do we also do all day long? We acquire information. We put it into our view of the world. We want to get smarter about stuff. Everybody from the ditch digger to the professor, we're trying to gather information and make the best decision about an upcoming event. Fine! Your responsibility is to acquire information, and make a good decision, based on a set of rules that you've bought into. We're going to hold you responsible to that because we have a social group here that wants to keep these norms. So, you view it like that. The question, and the way you ask it, it doesn't mean anything to me. We are decision-making devices that try to make decisions based on the information we've gathered in our life. If I make one of those that harms another person, I'm probably breaking a social rule that I've learned in that process of learning about the world. I have to be held accountable, just like we would hold a wayward machine responsible. Get that machine out of here! It's screwing things up. You need to consider that most crimes aren't committed in front of policemen or witnesses. People know the rules and when they are breaking them.

I think these talks of free will and the religious connection are not framed correctly. About 10 years ago now, 8 years ago, anyway, somewhere around there, there was a meeting held at the Vatican Pontifical Academy of Sciences, and I was included. These kinds of questions came up, and various people were there with different points of view. The Vatican has this hands-off relationship with the Pontifical Academy. While it's run by the church and supported by the church, it's independent of the church, even though there's this obviously philosophical view that they hold. But they want all comers to come and discuss, and so we all went, a bunch of us. There must have been 10 or 15 of us at the meeting. The funny story I tell at the end of all this, the occasion occurs where you get to meet the Pope. It was Pope Benedict at the time. We're all there and wondering what on Earth you're going to say to the Pope or what is the Pope going to say to you? Then it's your turn, and you stick out your hand and shake the hand of the Pope. He looks me right in the eye and says, "Keep up the good work." [laughs]

ZIERLER: [laughs]

GAZZANIGA: Wow! This is really something. Then—I like to tell the story—a month later, he resigned. [laughs] There is one way we like to think of how these stories unfold with the characters behind them and their limited view of the world, but when you're actually in the room with them, if they're normal people, they have a light touch about it all. You can be perfectly comfortable with having people around who don't buy the story as you try to tell it to them.

That's just a human relation. I remember when Sperry went to Pontifical Academy. He went around ‘64, and I was a student at the time. He came back, and he too was completely impressed with the experience because it's so high-level in one sense and so casual in another. You're just sitting there in awe of the history of the whole thing and your small role in it.

ZIERLER: Mike, was thinking about free will a gateway to thinking about consciousness, for you?

GAZZANIGA: No. The notion of personal responsibility is everywhere. It came up in the law project, it came up in the Bioethics Council, it came up all the time. People started doing experiments about how do people behave if they believe there's free will versus don't believe there's free will, and how do they behave in all kinds of tasks? All kinds of experiments showed that people behave more responsibly if they believe, they're told there's free will, versus another group randomly picked that isn't told that. The social value of the concept, regardless if it's true or not, is obviously there. It has a positive effect on people to act more responsibly. Therefore, people are highly willing to say, well, is it actually true versus this way of just saying it's true? So it turns out it's true. Things are better if you just say it's true, so let's see if it's actually true so we can tell everybody [laughs]—that kind of puzzle. It's just going to be around for as long as we don't have some definitive epiphany on how to think about it.

ZIERLER: Consciousness is something that, you know, the quest to find it has been around as long as humans have been around. What are the unique perspectives of split-brain research to identify what exactly consciousness is?

GAZZANIGA: This gets to the core of what I've got to resolve in the book. But, for me, at this point, whatever it is, you can have two of them. Whatever it is, if certain fibers are not severed, you seem to only have one of them. What does that mean? What that means is both hemispheres of the brain can manage and generate whatever it is on its own. Maybe it gets even more selective. Whatever it is is being managed throughout the brain in all these specialized systems we know each half-brain has. What does that mean? If you look at the brain as a vastly parallel distributed system with all kinds of skills, each one of them has the ability to generate the feeling of being self-aware about the skill.

You can say that more specifically. Consciousness is the feelings about specialized capacities. That may mean it's all over the place in the brain and little local circuits have the ability to generate that. What consciousness is, as you and I experience it through time, moment to moment, is whatever thing is up in our brain, allowing for the actions or speaking or thinking that we're doing at each moment. Each specialized capacity we have acquired over time has its own system to give us that sense of being conscious. It's through time that the consciousness that we come to think of is actually happening. That would argue for the kind of thought that, in an instant of time, there's no consciousness; it's only through time that you get it. Whatever the mechanisms are that produce that thing are all over the place in the brain. That's what my chore is, task is: to try to put more neuroscience hardware behind what I'm trying to stumble through here, more than I currently have or am able to. I'll leave it at that.

ZIERLER: In the way that you modify consciousness with the book, The Consciousness Instinct, what does that mean exactly? Is it that consciousness is instinctive, or there's an instinct to think that we have consciousness?

GAZZANIGA: It's more the former, that there are all these networks in the brain that are capable of and are doing all kinds of things. I use as an example— recent findings show that there's something like, I forget, 28, or something, circuits in the fly brain. All you need to do to produce the array of behaviors that a fly can come up with is to play those circuits in various orders and sequences, and you'll have plenty there to work with to produce all the things a fly can do.

Maybe we have those same kinds of circuits too, and each one of them would be an instinct. As often is said, we humans have vastly more instincts than an animal; not less. We think, oh, we're liberated from that. No! Probably there's a gazillion things that we have evolved and have in our brains that allow us to play this orchestra we call consciousness. They're instincts, so let's call them that. Let's call it out. That's the idea I'm trying to play with there. Then it turns out, you go back to William James, the son of a bitch said everything first. [laughs] He had a similar kind of notion, it turns out, and I refer to that in the book. It's much more fun to discover that he had a similar notion after you had your own thought [laughs] than before. That's what Sperry always used to tell me. He said, "Don't read anybody before you do the experiment. Just go do the experiment. Then you've got to go read what everybody says."

ZIERLER: That's right. [laughs] Mike, we've come up in the chronology, of course, sadly, to when the pandemic hits. You've written about humans as being the party animals. Of course, COVID was a time of social isolation. I wonder, personally for yourself, in how you viewed its impact on society, if COVID and all of the forced social isolation made you rethink things about either split-brain research or consciousness or free will.

GAZZANIGA: The quick answer is no. But we – my wife and I – were able during COVID to live a ridiculously normal life because we kind of live up on a piece of property that allows us to be isolated already. In some sense, our day-to-day life wasn't that changed, and then with Zoom you could call in to your job and everything else. The biggest thing about COVID that impacted us—and I think everybody else too—is this kind of black hole of memory, you know, that you can't remember the order of things. When did that happen? Wait! Was that pre- COVID? No, wait! Did that happen during COVID year one or two? All these reference points that we normally have are gone because you're not moving around in the culture with signposts to help you with your memories.

To give a concrete example of that, in the medical school business, a big part of medical training is for people to go on rounds with a professor, for the interns and the residents to walk around each morning, see the patients in the bed. I asked one of the neurologists when I used to be at Cornell about this. I said, "Why don't you just have one room? Everybody comes in, sits down, and you roll the patients in? Why this rounds thing?" The point was made that the memory for the cases stinks when you do that. I took that metaphor kind of like Zoom. You're sitting, and everything's the same, the same place, same this, same that; the next experience is just another person talking on the same screen with you sitting in the same place. How can you possibly remember it all? Of course, the fact is we don't remember. Our memory stinks through a lot of it. Those kinds of effects, certainly, one becomes cognizant of, are annoying. Maybe your memory is a hell of a lot better than mine. But I bet if we tested you, you would find things during this last four or five years of, "Wait a minute! When did I do that?"

ZIERLER: Right. It seems like a blur.

GAZZANIGA: Seems like a blur. Other than those things, I don't have anything specific with respect to the split-brain story.

ZIERLER: Did the pandemic influence the timing of your retirement, or that was already on a separate track?

GAZZANIGA: The thinking was ‘I should retire, because there's other people in the pipeline here who should take the resources that I was managing and let's see what they can do.' Real strong feeling about that, actually. Move over. There are all these bright people behind you. That was a big part of it. Then the aging thing rears its ugly head. [laughs] You don't have the total energy you used to have, and all that kind of stuff, so you just want to take it a little slower.

ZIERLER: That brings the story right to the present. To the extent you're capable of or willing to share, tell me about this new book project you're working on.

GAZZANIGA: I've been working on it now for a couple years, and I've written a chapter and kind of the pitch for the book. Still not happy with it. I'm trying to get the tone right. All my books are generally written for the general reader. I don't see any reason not to do it that way, or maybe I can't do it any other way! I'm not that kind of writer. But this one, I'm really puzzling how general it can be while making the serious points I want to make. I've been asking a lot of people, people I respect whose books I like, and so forth. There are at least two kinds of writers, I can tell you that. One type, they do not know where the book's going to land when they start it. The other type, oh yeah, they know. They've outlined the whole thing. The latter are principally, I think, more professional writers. They've got an assignment, they're going to tell the story, and they know how to tell the story. They have the skill. That's the way it is. Then the other writers, some of them are better than others. Some of them are great writers. But they can't quite see yet where it's going to land, and they work it through as they're writing. I'm in that category, for whatever it's worth.

ZIERLER: In retirement, do you still have mentor opportunities? Are you interacting with younger colleagues and students?

GAZZANIGA: Constant requests for that, and it hurts that you can't do that, because so much comes from that, so many inspirations, discovering that someone doesn't even know about something and then you bring them along into it and the joy of seeing the enlightenment. Yeah, it's hard not to do that as much anymore. I am still doing way too much editing. PNAS has this bottomless need to have editors set up for reviewing papers, getting that part of the scientific enterprise done. To get out of that obligation, you've got to show some spine, and say, "All right, I'm done!" [laughs]

ZIERLER: [laughs]

GAZZANIGA: Because it's an endless request to help out. But I do have the time to do it, and you actually start having lots of theories about the nature of the scientific enterprise, per se, and where it's coming from, and who's involved, and how this is actually going. Then you come also to the realization that there are plenty of, I mean, thank God, there are plenty of good citizens in science that take on the work more than they have to, or more than they should. They don't have to do the work, and arguably they shouldn't, because they're busy too. They have their life. But they do the extra work to keep science going. Then, of course, the status of American science is so high in the world that everybody wants to publish in the prestigious American journals. We've got just a ton of papers.

ZIERLER: You're keeping busy, it sounds like.

GAZZANIGA: Keeping busy, absolutely!

ZIERLER: Mike, for the last part of our talk, now that we've worked right up to the present, I want to ask a few retrospective questions, and then we'll end looking to the future. Let's start, of course, with what brought us together, Caltech and, of course, Roger Sperry. I wonder if you can just reflect on Sperry's legacy, and his work specifically as a product of Caltech.

GAZZANIGA: Of course, his legacy is untouched. As I wrote in my appreciation of him for Science after he won the Nobel Prize, all of his students were saying, "Which thing did he win it for?"

The Legacy of Defining Important Research

ZIERLER: [laughs]

GAZZANIGA: I didn't know yet—because he did the foundational work on neurospecificity (how neurons wire themselves up) and the split-brain stuff, and he did the work showing gestalt visual theory was wrong, and so forth. There was that legacy and then his later philosophical work after all of his famous scientific work. I think Caltech played a huge role in his long-term—the foundations of his legacy. Everybody was there at Caltech. The faculty is just stupefying when you think about who was in the biology department. You're playing tennis with all the best players, scientifically. Your game's going to get better. I think that is so true at Caltech, it's almost laughable. You've got to be on your toes all the time. I think he made use of that. I have memories of him walking down the central area there on his way to the Athenaeum for lunch with colleagues from biology. I have memories of him always disappearing for his swimming. He was very physically active, he had to because of his earlier bout with tuberculosis. I knew exactly when he was back in the lab because he always left his door a crack. He was always welcoming of long conversations. I talked to him all the time. That's just the personal side of it.

But, to me, Caltech provided this incredible experience, which I had there, and I can just imagine it was more of the same for him in spades. He was a—I don't know what the word is—not aloof but distant too. He wasn't a chatty, gregarious person, the type where you go in and start talking about what happened during the football game that weekend: None of that. I think the Caltech professors had one thing they imbued you with at every corner: Is what you're working on important? That's the killer question. They'd listen to you, you know, you've got some idea.

Maybe you're getting off on some tangent that you found, some rabbit hole, basically. Then you'd go present to them or at a lab meeting, and there'd be that look. [laughs] Yeah, that's a problem. You're doing an experiment on it, but is it important? That kind of way of saying that with a flick of an eye or a grimace, you know, it was always around. The eyes glaze over a moment. That was everywhere. Sperry had it. Van Harreveld had it. Delbrück had it in spades. Oh boy, he was a tough one. Pauling had it. Strumwasser had it. I mean, come on! These are experiences that are second to none. Your fellow grad students and your fellow postdoc, they're all in the moment too. It was serious stuff. Not without fun and humor, but just serious. You didn't screw around is what I'm saying.

ZIERLER: Mike, pure speculation on your part, if I may. It's been 30 years since Sperry's passing. If we could bring him back, and ask his perspective on the developments of the field, what do you think he would see as a very natural progression, and what do you think would take him by surprise?

GAZZANIGA: On the first one, the natural progression story so there's technological developments going on all the time, and they can be quite intense. You've got to learn a lot of stuff to make this machine work and a lot of new data analysis techniques. Take me as an example. I can walk into a lab here at Santa Barbara where all that's going on. You raise your hand. You can ask a question. You can be right in tune with what the point is of the talk. That's the point. The questions haven't changed that much; it's the technology that tries to illuminate them. You know if they're illuminating the question, and you can key into a modern conversation about whatever it is they're presenting, because you know what the question is.

We're still trying to answer these big questions, even though there's new and complex technologies. However, don't expect a question from me about the complexities of the techniques being used!

There's a continuation in this field, where the questions are much larger than our capacity to answer them in a concrete, in a specific way. What would he be surprised by? Maybe things that come to mind, of course, are all the things that are happening in AI. That was just a joke 30 years ago. It was a joke 10 years ago. Now everybody's just puzzling it. What does this mean? I heard a talk last Friday that's just stunning in an aspect of what we can learn from artificial neural networks that mimic human phenomenon of emergence. It just stops you in your tracks when you hear these talks. Where is it all going to land or sort out? We're in the middle of it. I don't know. But, certainly, jumping ahead are the same things I'm stunned about, and the field is stunned about, would certainly be there. There was just no imagining this 30 years ago. Maybe sci-fi 10 years ago saw it coming, but not the workaday people.

ZIERLER: Mike, the focus of our discussions has been, of course, on all of the discovery. Are there aspects of split-brain research that feel as fresh or as unanswered or as much of a black box as when you first considered them way back in graduate school?

GAZZANIGA: Yeah, sure! We get to the subjective reality question, the you. That's what we all are. We spend our time all day long in that subjective moment, and—what is it that that thing's going to be? Is Dan Dennett going to win and say, "Well, when you just put all these calculations together, this falls out of it, and there's no place in the brain where this happens"?

It's what the brain does, period. It's everything. It's everywhere. Not that you are everywhere, in your brain. What we think of as you – your conscious experience – just kind of falls out of all the other stuff? Or is there going to be a set of networks that can be spelled out, articulated and, if wired together, we can build one of these things? Is there a specific place or network or process that creates consciousness? No one has the slightest idea actually how it'll work, in the end.

In that sense, the split-brain work becomes, to me, every bit as alive, because whatever this thing is, we can make two of them. Now, what does that tell us? We can maybe even do more than that with other cuts. What does that tell us? I go back to my book idea. I think there's a point when the penny drops, you get it. You say, oh, that's what that means. You can be saying concepts for years and years and years and years, and, all of a sudden, there's this epiphany. Oh! That's really what that means. There is a dimensionality to it, a fullness that we're not there yet on how to think about things like subjectivity. Okay, we can make two of them. Okay, we can maybe make more. What is that though? How are we supposed to think about that? Anyway, that's what I'm trying to add some light to.

ZIERLER: Mike, your career trajectory is the opposite of being hired as an assistant professor in one place, and spending your entire career there.

GAZZANIGA: Yeah! [laughs]

ZIERLER: What has been the effect or the impact or the net benefit of having moved around so often in your career? What's been the value to that, and where would you tend to de- emphasize the significance because the ideas travel with you?

GAZZANIGA: There are so many aspects of academic life that I don't find interesting. Moving from one point to another point gives you the opportunity to have a fresh relationship, fresh issues, fresh this, fresh that. Over the years, our moving around, it was always to something new and exciting, a new project, a new dimension to the job. When you do a piece of research, and you've defined the problem you're interested in—when I left Caltech, we had done the split- brain thing and had thought through what it meant and its many implications. Then going to New York and finding a whole new group of patients to study that were varied and different brought a whole new different meaning to some of the split-brain work. Then being asked to do these extra scientific things like serve on Bioethical Councils and this Law project you just mentioned, and other things, all that is enriching. They all came in different places and probably through different connections that I came across by moving around. The excitement of working at a medical school versus an arts and science department was a big change in my life and my thinking. Spending 10 years at Cornell Medical School in New York was a big deal. You thought you understood the neurologic underpinnings of consciousness. Then you see this whole different story, observing lots of different ways people respond to damaged brains. So, I found moving around enriching. Then I had the brains [laughs] to, while that was all going on, hold onto my house in Santa Barbara, so I had a place to come back to and here we are.

ZIERLER: Mike, the duality of your intellectual output, you know, directing graduate students, working in technical environments, writing scholarly papers, and then, on the other hand, all of the books that you've written that are geared toward the broader audience, do you generally view your impact the way that you've shared your ideas in those separate categories, or is it really, at the end of the day, all about the production of knowledge for you?

GAZZANIGA: It's all so different. Each task has its constraints on it. But I would say, I would think maybe you put your finger on it more in the latter category, that you're contributing to knowledge, to understanding. For me, it's all based on the appreciation of the role of the brain in it all. I really hold onto that one. As humans and in our culture, to not appreciate the fact that all these things we're so agitated on are due to some circuits in the brain is, well, lame. Chill out! If you understand that you want to manage it all, be part of it all but you realize the underpinnings of it all, then it brings a calmness about it all, at least it does to me. That's what motivates all these extensions into other things. That's my stance on it. Everything from—you know, I wrote a couple editorials for The New York Times on the embryo question, and I wrote a book on The Ethical Brain, all about this stuff. Come on, guys! Get with the program here. This is what we know, and this is where science may start touching these interesting questions. But let's come talk about it. You think of some of today's politicians. Can you imagine having a discussion about neuroethics with them?

ZIERLER: [laughs]

GAZZANIGA: No! Forget about it. But that's the goal, you know, quite a goal.

Unlocking Ourselves from Fixed Concepts

ZIERLER: Mike, for the science, all that you've worked on, where do you think you've moved the needle the most?

GAZZANIGA: Certainly, the split-brain human work was the big event that I was lucky to be part of very early on and held that close to what I think about all the time. I don't know. I think about the brain basis of things as they apply to all kinds of stuff all the time. That's just what I do. That doesn't mean I don't have a whole lot of fun. I like to do a lot of other stuff too. But it's kind of what you do. That's what you were trained to do. That's what you want. By the way, the idea of training, and who you are, I think the who you are comes first; then the training. You have this impulse. There's something there you want. There's something, a part of your personality trait or your view, where you went after that. Then lots of people shaped you, and contributed to it, and all the rest of it. But I don't think you take a person interested in rocks and turn them into being interested in dynamic brains. It starts with an impulse that comes with you from the baby factory, and then you try to do something about it.

ZIERLER: Finally, Mike, one last question, looking to the future. Using your powers of extrapolation, given how long you've been at it, where is the field headed, and what are you most excited as you look to the up-and-coming generation and what they're doing?

GAZZANIGA: I mentioned to you earlier that one idea I sort of got off the ground just as I was retiring was to have these sessions where you would take that question and bring people together to think about it. Have four or five people think about, how are we locked into current concepts? How are we not liberating ourselves by not mixing our ideas more fruitfully and often? There is the famous statement by Wolfgang Köhler. The best science comes from trespassing, people mixing ideas from other fields and liberating themselves and seeing things, because it is a fact that if you're working on a scientific problem, you have to focus on it.

There's no mystery as to why people get channeled, and why frameworks start. There's no mystery at all why that happens. In some sense, it has to be part of it. But how can we have regular—built into our institutions— regular life rituals that liberate us from that? I was thinking towards the end of my official academic career having a Friday afternoon session called The Pitch. The pitch idea was stolen from Hollywood, right? You're pitching a new movie here. In a science setting, you've got to come and tell us what's your new idea and have it blow in the face of everything that's going on around you. Just as an exercise that is given mutual respect by everybody in the room. It would go a long way for people just to have a larger canvas to draw upon for their future thinking. Yes, I am avoiding your future question because that's only a bum's game.

ZIERLER: [laughs]

GAZZANIGA: No one ever gets it right. [laughs] Something happens. Holy cow!

ZIERLER: It's been interesting the whole time. It'll continue to be interesting.

GAZZANIGA: Yeah, absolutely! Don't worry about new things. I'll end on this note, because it just came up. Go back to the Neuroscience and Law thing—how much is neuroscience going to change the courtroom and the legal system? Well, this big, bright, shiny new thing, neuroscience, it's going to solve everything, kind of thing. Actually, I'll bet you in the next 10 years, the deeper question will be, how will AI challenge the legal system? There's going to be large language models that make predictions about recidivism, about parole, about all these things that are probably better than any of our current experts, and all the rest of it. Will that be allowed to happen in the courtroom, and all the forces that will be against that, and so forth and so on? I think there'll be changing questions that we can't quite yet imagine. But, on that one, I'm pretty sure that's going to be a big one.

ZIERLER: Mike, it's been a wonderful series of discussions. I'm so glad we were able to do this, and to have you share all of your perspective and insight. I want to thank you so much.

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