Making Sense with Sam Harris - #91 — The Biology of Good and Evil

Episode Date: August 9, 2017

Sam Harris speaks with Robert Sapolsky about his work with baboons, the opposition between reason and emotion, doubt, the evolution of the brain, the civilizing role of the frontal cortex, the illusion of free will, justice and vengeance, brain-machine interface, religion, drugs, and other topics. If the Making Sense podcast logo in your player is BLACK, you can SUBSCRIBE to gain access to all full-length episodes at samharris.org/subscribe.

Thank you. of the Making Sense podcast, you'll need to subscribe at samharris.org. There you'll find our private RSS feed to add to your favorite podcatcher, along with other subscriber-only content. We don't run ads on the podcast, and therefore it's made possible entirely through the support of our subscribers. So if you enjoy what we're doing here, please consider becoming Today I'm speaking with Robert Sapolsky. Robert is a neuroendocrinologist and a primatologist. He's a professor of biology and neurology at Stanford University and the recipient of a MacArthur so-called genius grant. I don't know if that's the official title of that grant. Does one have to say so-called genius grant. I don't know if that's the official title of that grant. Does one have to say so-called there? In any case, Robert really is a superstar professor

and communicator of science, as well as a top-flight scientist. And as I say in the beginning, I remember being in a class at Stanford when he came in as a guest lecturer, and I recall that being one of the moments that nudged me toward doing my PhD in neuroscience rather than philosophy. I've been wanting to speak to Robert for quite some time. He's actually been one of my most frequently requested guests. In this episode, we discuss his new book, Behave, The Biology of Humans at Our Best and Worst, which I highly recommend. It really is the most accessible discussion of brain science you will find. And for those of you who want more talk about free will, about the fact that the concept doesn't make much sense, and about why that matters, we get into that at the end.

And now, without further delay, I bring you Robert Sapolsky. I am here with Robert Sapolsky. Robert, thanks for coming on the podcast. Sure. Glad to be here. As you and I know, but our listeners don't, we have been fighting our robot overlords to get a clear connection here. Now, with two attempts, and I think we've got it, but as I've said, if this glitches on us, I will get on a plane and come and interview you because we have a lot to talk about. So welcome to the podcast. Thanks for persisting here. I'm trying to check my memory here. I don't think you and I have ever met. We were in very much similar circles, but I recall actually when I was at Stanford, I was in a class with John Gabrielli, I think on

the neuroanatomy of memory, and you were brought in as a guest lecturer. And so that was my first exposure to you and really fairly early exposure to what is interesting about brain science. You gave this very cool interdisciplinary talk because you are both a neurobiologist and a primatologist. And just you should know that you stand in front of a class of undergraduates for the better part of an hour, got into my brain and inspired me in part to go the direction I did. So thank you for that. Well, thanks. That's really good to hear. So you've written this book, Behave, which is just this monumental tour of the human brain and behavior. And we will cover some of it. We definitely will not exhaust what is interesting

in that book. But what you did here is, as I know all too well, it's really hard to write about the brain in a way that's accessible because it's not so much that the concepts are so hard, but once you get into the details and you start naming parts, it just becomes this thicket of neuroanatomical terms and people totally lose the plot. You really do a fantastic job in this book of giving scientific detail in a way that is not at all boring and really quite accessible. And honestly, this is not something I have managed to do in my books. And that's why when I bring in the relevant neuroscience, I kind of get in and get out as quickly as possible because it makes for brutal reading. but you've struck a wonderful balance

here. So more praise to you. Well, thanks. I have had to survive neuroanatomy classes, so I know exactly how awful all the multi-syllabic names can be. So I'm still traumatized myself. Yeah. So I want to talk from before we get into your book, just about your background here and the way in which you've married what is essentially neuroendocrinology and primatology, which is a fairly unique combination. I can't imagine there are too many of you at meetings with the same bio. How has primatology informed your study of the brain? And if I'm not mistaken, you focus exclusively on baboons, right? So how has the picking of baboons been relevant here? Well, sort of the common theme in my work has been to understand the effects of stress on health,

in particular, the effects of stress on the brain. And what do you know, the punchline for all of that is stress can do some pretty lousy things to the brain. What I've spent many decades doing is, as you say, sort of oscillating between being a lab scientist, growing neurons in petri dishes, mucking around with their genes and such. And then for 32 summers, picking up and going to a national park in East Africa and studying baboons there. And these are the same animals I return to each year, animals I can dart, can anesthetize. And when they're unconscious, do a whole bunch of like basic sort of clinical tests you do in a human. In terms of balancing the two, they've always kind of complemented each other

in that you observe something or other interesting about the brain based on your petri dish neurons or your lab rats. And that's great. But the question of course, is whether this this actually tells us anything about the real world. Let's go study a primate in its natural habitat. And then you see something interesting behaviorally with these wild primates. And you say, geez, I wonder if it's this part of the brain or what's going on there. And thus, you go back to the lab and your cultured neurons. So it's been sort of a very privileged ability to do these sort of complementary approaches. I'm now picturing you darting these baboons. Do you do it yourself? Do you actually fire the gun?

It's a blowgun. It takes surprisingly little practice. Fortunately, baboons have very large rear ends, which is what you aim for. And you're beyond cliched as like you're nice liberal. And so the ability to like sort of sneak around the bush with a blow gun and shoot at wild baboons and like do that. It's great. It's like, and, and you're doing conservation work the whole time. So it's a, yeah, it's a blast. I love doing it. Now, do the baboons recognize you enough to, and recognize what you're doing enough for the consequences of your darting to form a grievance against you darting them? of your darting to form a grievance against you darting them?

Not if things go well. I mean, sort of 90% of the time out there, you're collecting behavioral data, which is your basic Jane Goodall sort of scene where you're just hanging with them from dawn till dusk. And there's sort of a whole science about doing it in a quantitative, objective kind of way. So it's actually an infrequent day where i'm out darting but one of the things um that actually makes it quite difficult is you can't dart somebody until there's nobody else around and nobody looking and he's turned the other way

you dart him and he responds as if he's been stung by a bee or has sat on a thorn, jumps up, scratches his rear for a second, sits back down, and then three minutes later he's unconscious. So you get one alone and when he's unconscious you can approach him and no one else intervenes from the troop or notices what you're doing at that point? Well, that's when it all goes perfectly smoothly. When it doesn't, he decides to pick up in those three minutes before going under and walk over and sit down right in the middle of a gazillion other baboons or get into a fight with somebody. And those are the ones that don't go so well.

What are you doing to the reputations of these baboons that walk among their troop and start a fight and then promptly faint from your anesthesia? Well, it's got to cause all sorts of interesting belief systems in these animals that I can't quite access. That's funny. Now, are there disanalogies between baboons and humans that are of interest here? Because they're further from us than chimps. So are there ways in which chimps are similar to humans and baboons aren't? And if so, why the choice to study baboons? Chimps would be much better insofar as the cliche, they share and do share 98% of our genome with us, far closer in terms of social structure, in terms of cognitive, emotional capacities, all of that.

Nonetheless, baboons still count as close relatives. I think we 96% share DNA for a bunch of reasons. Baboons are perfect for what I do. They live out in the open in these big open grasslands. So you can see them 12 hours a day and you can actually like see them to dart them. They don't live up in trees. They're not endangered.

They're big. They've got lots of blood that you could borrow from them for your sort of tests. But probably most of all, given that I study stress, none of us are getting stressed because we're like riddled with, you know, diphtheria or some horrible chronic illness. None of us are getting stressed because we're chased by saber-teeth tigers every day. Instead, we're westernized humans, which is to say we get chronic psychosocial stress. And it turns out baboons are absolutely perfect for this. They live in these large troops, 50 to 100 animals. The Serengeti where they live is like

a perfect ecosystem. Predators don't hassle them much, and they only have to work about three hours a day for their calories. And what that means is you've got nine hours of free time every day to devote to making some other baboon miserable. All they do is generate social stress for each other. They're perfect models for westernized humans. Now, what about mandrills? They look like baboons, but they're not baboons, right? Am I right about that? Oh, there's some major taxonomic civil war going on about that as to whether they are a baboon type.

I've steered clear of that one because I'm fairly uncommitted to it. But they're a different social system. They live in dense rainforests. They would be mighty hard to study. These savannah baboons that I focus on are perfect. So now getting to your book, which is really this wonderful tour of the brain and behavior and morally salient behavior, you and I approach these questions from a pretty similar angle, and we agree about many things. I'm sure we'll talk about free will at one point because many of our listeners want us to, and you are one of the few people who have made more or less the

same noises on this topic that I have in science. We've broken the same taboo here. That'll be fun to talk about. But to start with where you're coming from, you have a kind of unity of knowledge approach. And you look at the various levels of scientific explanation from neurophysiological and genetic to psychological and cultural. And each of these clearly has a different language game associated with it. But you, like I, don't make much of the transitions between these levels. But you do something interesting here where you find a novel way of segmenting these different levels of analysis with respect to time, the proximity to causing human behavior, which is very interesting. So talk about how you break down the levels of scientific explanation in a temporal sense. As behavioral biologists, which most of us are in some stripe or other, a behavior occurs and

we are in a sense asking, why did that behavior just happen? And it turns out that's actually asking a whole bunch of questions. Because if you're asking, why did that behavior just happen? Part of it is what occurred in the brain of that individual one second ago. But you're also saying, what were the sensory cues in the environment a minute ago that triggered those neurons? And you're also asking, what did that person's hormone levels this morning over the recent hours or days have to do with making them more or less sensitive to those sensory cues, which then trigger those neurons.

And then you're often running to neural plasticity over the course of months, back to childhood, back to fetal environment, which turns out to be phenomenally influential on adult behavior. And then you're back to genes. But then if you're still asking, why did that behavior occur? You're also asking, well, what sort of culture was this person raised in? Which often winds up meaning what were this person's ancestors doing a couple of hundred years ago? What were the ecological influences on that? And finally, when you're saying why did that behavior occur, you're also asking something about the millions of years of evolutionary pressures beforehand. So it's not just the case

that, ooh, it's important to remember to look at these things at multiple levels. Exactly as you said, ultimately they merge into the same. If you're talking about the brain, you're talking about the childhood experiences when the brain was assembled. If you're talking about genes, you're implicitly talking about the evolution of them. All of these just are a confluence of influences on behavior that are all sort of interconnected. Yeah, yeah. Well, we'll get back to that, precisely that picture when we talk about free will, because obviously there's a lot of confusion about degrees of freedom for the mind when you're talking about

the neurophysiology of human behavior or the way in which culture influences brain development. The punchline here, obviously, is that once you grant that the brain is the final common pathway of all these influences, when you're talking about human thought and intention and behavior, well, then you have to grant that what the brain is doing is the proximate cause of what the person is doing. And either you're going to sign on to the laws of physics here or you're not. So we'll get back to that. But there's a common misunderstanding around the relationship between reason and emotion, just across the board, but in particular with respect to human behavior and the answering of moral questions, the way in which we just form a worldview that is this idea that you can be

emotionally motivated or you can be motivated by emotion-free rationality. Let's perform a little psychosurgery on that idea. You treat this in your book. How do you think about reason and emotion? Well, it's the inevitable Coke versus Pepsi dichotomy there, and as to which is more important, which influences the other more in terms of our actions. And of course, it turns out, as with most sort of dichotomies with behavior, it's a false one. They're utterly intertwined. And intertwined on a neurobiological level, you have a thought, you think of something terrifying that happened to you long ago and emotional parts of your brain activate and you secrete stress hormones.

Or you have an aroused emotion. You're in an agitated, frightened state. And suddenly you think and reason in a way that's like imprudent and ridiculous. We make terrible decisions often. When we're aroused, the two parts are equally intertwined. Probably where the most progress in thinking about this intertwining has come in recent years is there's a certain sort of comfort and I think chauvinism we take as these creatures with big cortexes and thinking that nonetheless reason is sort of at the core of most of our decision-making. And an awful lot of work has shown that far more often than we would like to

think, we make our decisions based on implicit emotional automatic reflexes. We make them within milliseconds. Parts of the brain that are marinated in emotion and hormones are activating from the standpoint of the brain long, long before the more cortical rational parts activate. And often what we believe is rational thinking is instead our cognitive selves playing catch-up to try to rationalize why our emotional instincts actually are perfectly logical and make wonderful sense. And in lots of ways, the best way to show this is you manipulate the affective, the emotional, the automatic, the implicit, the subterranean aspects of our brains where we

may not even be aware of it. And it changes our decisions. And then we come up with highfalutin explanations for why it's actually because of some philosopher we read freshman year, that's why I did what I just did. No, actually, it's because of this manipulation that just occurred. Yeah, yeah. So there are really two sides of this. So that's one side, which is kind of deflationary of cognition and reason. So you think you're reasoning and that your reasoning is driving your cognition or your belief formation, but then when you look closely, you find that it's being driven from below

by emotion. But the flip side of that is that in order to make even the most coolly calculated reasoning effective, it needs to be integrated with parts of the brain, in this case, the ventromedial prefrontal cortex, that you need a felt sense of the consequences of being right or wrong. And this connects to Damasio's work and others where people who have neurological damage there, they may know the correct strategy, say, in a gambling task. They may understand the probabilities, but they can't make that understanding effective because it doesn't actually mean anything. It's not coded appropriately. Yep. And it turns out this is like a tremendous rebuke for the people out there who would say,

if only we could be purely rational creatures, if only we can get rid of all that affective muck from underneath, why we'd all be Mr. Spock and it would be a wondrous world. And exactly as you say, ventromedial prefrontal cortex, work of people like Damasio, people who have damage to this part of the brain that's basically the means by which your emotional parts of the brain talk to your most rational ones and tell them what they're feeling get damaged there. And people make decisions about things that we view as appalling, as beyond the pale, of cold-blooded, as detached. pale, of cold-blooded, as detached. As one example, you take any normal person on earth and you give them sort of a philosophy problem. Would you kill one stranger to save the life of five? And they maybe say yes, maybe say no. And then you say, would you kill your parent, your loved one to save the life of five? And in half a second, you say, no, of course not.

It's my mother. It's my child, whatever. And you take somebody in damage to this part of the brain and they give the exact same answer. It doesn't register. They don't process relatedness in the same way. And every primate on earth would look at that and say there's something desperately wrong with this person's brain. On this issue of emotion and rationality, one point I have begun making, which I haven't heard made, and I just want to bounce it off of you. I've begun to think about doubt, which really is one of the core foundations of our rationality, right? I mean, so you say something which I find implausible, you know, kind of my error detection mechanism, whether it's logical or factual or semantic or based on memory, you know, something gets tripped. You say,

you utter a sentence and I don't buy it. That feeling of doubt, in my view, really is an emotion. don't buy it. That feeling of doubt, in my view, really is an emotion. And we actually have some neuroimaging data to back this up in that all the fMRI studies I did on belief showed that disbelief, doubting the veracity of a proposition, was associated with activity in the anterior insula. And I've actually begun to think of doubt as a kind of emotion on the continuum of disgust, as kind of propositional disgust or cognitive disgust. And, you know, frankly, when I see our president speak, I find I'm viscerally in touch with doubt as disgust, right? I mean, like there's a certain level of incredulity in the face of, you know, a confident utterance that precipitates in me, at least,

a fairly strong emotion of disgust. So I want to put those data in front of you and just get your take. Well, my insular cortex is right with you on that one. But I thoroughly agree with it. Obviously there's some domains where doubt is just a purely rational process. You sit there and you add up two and two and somehow it comes out to five. And that's a fairly pure cognitive state of saying, I doubt if that actually is correct. But most of the doubts we have in our social world, I think you're absolutely right, is

steeped in emotion. Emotion, disgust, perhaps, at the person who is sowing that doubt. Emotion... Robert, just to clarify, if we put you in a scanner and give you propositions just like that, two plus two equals five, you're six foot five inches tall, you're a woman with blonde hair, George Washington was never president of the United States. I just give you propositional statements which you recognize to be untrue, but which are not, in fact, emotionally laden. I would certainly predict, on the basis of now three neuroimaging studies, that those would be associated with insular activity in you and the same statements in a positive light that you would accept, you know, George Washington was the

first president of the United States, wouldn't. I completely agree because it's very much context dependent. If I were sitting there on my own and adding up two and two and I got five, I would have, you would have a half second's worth of pure rationality. Wait a second, that's not right. And then I would have, that's it, I'm an idiot, I'm a fake, everybody else is going to finally figure it out, I can't even add two plus two. And sitting there in the brain imager, I think you're absolutely right. That would not be a purely cognitive experience. That would be, what are these guys up to? Do I trust them? Do I feel safe here? Do they think I'm an idiot? What do they think of me? Did I say something foolish before? Are they going to lock

me up in the scanner, et cetera? And often running with emotional aspects. I think one of the most perfect realms for looking at this is when you look at conformity studies and where people go along with something that is patently untrue, yet they go along, a certain percentage of them are just being affable, they're being publicly conforming, but a certain percentage actually change their minds and you can see activation of the visual cortex. Hey, remember, you actually saw something different than you're saying. You saw what all of them are saying. This is a state that's also associated with activation of the insular cortex, activation of the amygdala. It's anxiety. Doubting provokes anxiety. Certainty is a very comforting thing. And doubting, even seemingly the most cerebral and sort of soulless of issues out there, nonetheless readily taps into all these senses of anxiety running underneath there.

running underneath there. There's this other piece here, which is that the brain doesn't have, I mean, this is just a constraint of evolution. We were not built so as to acquire new cognitive abilities de novo. The only material to use for modern human cognition are these ancient structures that have to be commandeered to new purposes. So everything we do is built on the back of these apish structures. You know, here we're talking about the insula, which does receive the inputs from the viscera. You know, you find rotting food disgusting. You know, that is the tale told by the insula. And the only way to build a mind that has the capacity to find abstract ideas repugnant is to be repurposing or extending the purpose of these brain areas that were doing nothing of the kind in apes like ourselves that couldn't form abstract

ideas. Absolutely. And it's a totally fascinating domain, the fact that this insular cortex, which if you're a mole, will tell you if you're eating something rotten, activates in humans thinking about moral disgust, that a part of the brain that does temperature sensing for you is also activated when you're contemplating whether somebody has a warm or cold personality, that the parts of your brain, some parts that are involved in pain detection in a very literal sense also activate when you're feeling empathic about somebody else's pain. And all of these speak to this sort of old truism about evolution. Evolution is not an inventor, it's a tinkerer. It makes do with what's already there. When did humans come up with the concept of moral outrage and moral disgust?

Maybe in the last 20,000 years, 50,000, whatever, when did we come up with the concept of having warm or cold personalities? A lot shorter than that. And at that point, nobody sits down and says, okay, we need to evolve an entirely new part of the brain that does moral disgust. They say, insula, I know they do. That kind of sounds the same. They do food disgust. Like here, give me some duct tape. We're just going to push that into the insula. And now the insula also does metaphorical moral disgust. And it's a brain that's winging it in a lot of ways for some really interesting ways in which it's better and ways in which that's for the worse. When you think about the role of the brain in producing these kinds of purely human-level

distinctions, things like the birth of civilization, really, I mean, it's largely a story of what the frontal cortex is doing. I think you say at one point in the book that this region of the brain is what makes you do the hard thing when the hard thing is the right thing to do. Let's talk for a moment about the role of the frontal cortex in our species. That's exactly sort of a summary of what it does. More jargony, it does impulse control and emotional regulation and long-term planning and gratification, postponement and executive function. It's the part of the brain that attempts to tell you, you know, this seems like a good idea right now, but trust me, you're going to regret it. Don't do it. Don't do it. Of great importance, it's the most recently

evolved part of our brains. Our frontal cortex is proportionately bigger and or more complex than in any other primate. And most interestingly, it's the last part of the brain to get fully wired up. I mean, we're accustomed to images of, you know, your brain is pretty much set to go by the time you're at kindergarten. The frontal cortex is not fully online until people are on the average about a quarter century old, which is boggling, which is boggling, but it also tells you a whole lot about why adolescents act in adolescent ways because the frontal cortex isn't very powerful yet. But in that is an incredibly interesting implication, which is if the frontal cortex that does all this complex, like culture-specific reasoning and regulating of behavior, if the frontal cortex is the last

part of the brain to fully mature, by definition, it's the part of the brain that is least constrained by genes and most shaped by experience. And that's real important. Because think about, I mean, sort of, okay, the frontal cortex, it's your moral barometer, if that's the right metaphor. It's your Calvinist voice whispering in your head. So the frontal cortex, for example, plays a central role if you're tempted to lie about something. And if you manage to avoid that temptation, your frontal cortex had something to do with it. But at the same time, if you do decide to lie, your frontal cortex plays an enormous role in you doing an effective job at lying, because that's a version of frontal regulation

also. Okay, control my voice. Don't make eye contact. Don't let my face do something funny. That's a frontal task also. You know, if you're talking about a part of the brain that is both central to you avoiding lying, but once you've decided to lie, is central to you doing it effectively, this is a very human, very complicated part of our brains.

Yeah, and so to follow on what you just said there about the implications of it being so late to develop, this is really where it matters what culture you're in and what early life experience you have and what kind of person you become with respect to your beliefs about ethical norms and what constitutes honor and everything that stands out as a salient, consequential difference between groups and societies. Now, none of this is just floating around in the ether. It's not just in the books on our shelves. This is getting etched in the brains of all concerned. And largely, this is a story of what is happening in the frontal cortex. Yep. And that's exactly why it can't mature until you're 25. It's not that it's a more complex construction project than wiring up the rest of your brain is. You need the first 25 years to

learn your situational ethics and your culture-specific beliefs and that sort of thing. And those are subtle, and they're often unstated, and they're often exactly the opposite of what people tell you things are supposed to be about. I mean, think about it. Every culture on earth bans some types of killing and allows others, and they all do different ones. Every culture on earth supports some types of lying and bans others. In our culture, it's okay to lie to grandma,

to say, ooh, I don't have that toy, this is wonderful, thank you, thank you, when you've got the actual toy in your closet. And it's okay for us to lie if somebody says, are you harboring those refugees in your attic? And you say, no, of course not, sir. Of course not, SS officer. That one's okay, but there's other ones we ban. Every culture has prohibitions about sexual behaviors where some types of behaviors are wondrous and others are blasphemous. And they all differ. And that's a lot of subtle stuff to have to master as to what counts as doing the right thing. Although I'm doing my part to

not spare grandma the brutal truth about the toy. That's a meme I'm trying to knock down. I know your book lying certainly makes the most convincing sort of argument I've seen for it's not okay in any domain. Yeah, although I think there's a misunderstanding there. I think I saw in a footnote or an end note, you said that I'm against lying in all conceivable circumstances, kind of the Kantian view, which is not the case. I actually, if you're at the door with the Nazis and you've got Anne Frank in the attic, then I view lying the way most people do as an adequate and even necessary act of self-defense or the defense of others in those

cases. I really view it as being on a continuum of violence where it's the least violent thing you can do to someone who's no longer behaving as a rational actor or someone whose behavior you can modify with honest speech. Okay, sorry for that misrepresentation. Nobody was supposed to read the footnotes. Well, Anne Frank is safe in my attic. Oh, good. So now, are there primates that show an analogous delay in maturation in the frontal cortex or is that a uniquely human issue uh no it's primate wide

it's even rodent wide um but it's not as dramatic it's not as delayed it's not as faced with complex of the task as we do when learning uh sort of the the complexities of our frontal dependent prohibitions but no we're not the only species that invented the idea that this is a very good part of the brain to make very malleable in the face of experience. We've just got the most dramatic version. There are other interesting bits of neuroanatomy here that you don't often hear talked about, at least in the popular press. There's something called von Economo neurons, which are unique in primates and cetaceans and elephants, I believe. And they're,

I think, uniquely in the insula and anterior cingulate or preferentially there. And they relate to social cognition and self-awareness. Give us a potted description of what's happening there with these neurons. They're very cool. And you study human brains, and one of the first things you have to recognize is we're not humans because we've invented a totally novel type of neurotransmitter or a completely new brand of neuron. It's just that we've got more of them. They're more complexly wired. But then people found this one neuron type that did seem to be unique to humans, these von Economos. They're almost entirely found in anterior cingulate, insular cortex, having to do with empathy and moral disgust and all that cool, interesting stuff.

So that's plenty interesting. But as you say, then people looked further and it turns up in other species and all the usual suspects when you're looking for the most complex social worlds. Yeah. Other apes, other primates, cetaceans, elephants. And the best guess is that they play a role in some very complex aspects of sociality. Are they mirror neurons? Don't get me started on that one, but very little reason to think they play the very narrowly documented sense of what these mirror neurons do. That's a whole separate rant. But one of the most interesting things is these are the first neurons that die in a very obscure neurological disease called frontal temporal dementia and one that predominantly damages the frontal cortex

and the first neurons that go are von econimo neurons and two interesting things about that what that tells you is these are really expensive vulnerable neurons to operate if there's the for if they're the first ones that keel over. But the other thing is, what does the disease look like disinhibited socially inappropriate behavior? And often it's initially viewed as a psychiatric disorder until you realize this is a massive neurological sort of carpet bombing of the front part of your brain.

Whatever these neurons are doing, they are very, very much sort of carpet bombing of the front part of your brain. Whatever these neurons are doing, they are very, very much sort of specialized for the most complex social things we fancy species do. Yeah. Well, so I think the last stop on our Cook's tour of the brain here, or at least the Cook's tour of the frontal cortex is the dorsolateral PFC, which is associated with much of what we consider to be higher rationality or executive control. And activity here is able to dampen activity in emotional parts of the brain, like the limbic system, for instance, the amygdala in particular, reducing negative affect, it can do this by becoming active in a relevant way. And this is something that I think people understand, that if you cognitively reappraise what an experience means, so for instance, you think someone's being rude to you, then you reconstrue that, realizing, say, that maybe he's just nervous. And then that will dampen your initial negative

emotional response to what you perceive to be rudeness. But what's also interesting is that really any use of your dorsolateral prefrontal cortex can dampen negative arousal. I mean, if you're feeling negative emotion and you just put your attention on something else, you just start doing math problems or you do anything that requires an alternate form of cognition, that can have a similar effect of dampening arousal. In thinking about this, it's always interesting to consider how someone like yourself who spends a lot of time thinking about the mechanics of emotion and cognition from the brain side, does this ever become relevant to you in your life behaviorally? I mean, do you ever, is there anything that you do differently in your moment-to-moment experience,

given how much time you spend thinking about what's going on under the hood? what's going on under the hood? For better or worse, yes. The same thing has infested my wife, who's a neuropsychologist by training. When our kids were young, I remember this one day where our four-year-old son had just done something rotten to his two-year-old sister. We swooped in there and we were doing the, you're not a bad person, but you did a bad thing and wailing on him with that one. And why did you do that? And at some point, I don't even remember which of us said this. One of us would say, why are we getting on him so hard here? He has like three frontal neurons. And the other one's response would be, well, how else is he going to develop

a good frontal cortex? So we actually think that way in my house, which is pretty appalling when you think about it. Although, something I write about in the book where I have the most trouble applying my worldview as a mechanistic, reductive, deterministic sort of scientist guy thinking about behavior is, as you say, when it's getting to the realm of free will. Much like you, I don't believe there is free will. I believe free will is what we call the biology that hasn't been discovered yet. But what I find to be a hugely daunting task is how you're supposed to live your life thinking that way. And even me with like, I'm willing to write down and print, there's no free will, and here's why. You know,

at some critical juncture of some social interaction, I act absolutely as if I believe there's free will. I hear about somebody who's done something jerky and I wish horrible things to them instead of stopping and saying, oh no, but think about what happened to them as a second trimester fetus. It's very hard to function with that. Like most people, I hit a wall with that one. It's a whole lot easier to operate with the notion of agency. Well, let's jump in there because this is obviously a hugely consequential issue. Or maybe it's obvious to us. It's not so obvious to most people, I think, that coming to a different conclusion about free will has consequences. And I would argue they're quite good consequences. But let's get there.

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