The Joe Rogan Experience - #965 - Robert Sapolsky

Episode Date: May 25, 2017

Robert Sapolsky is a neuroendocrinologist and author. He is currently a professor of biology, and professor of neurology and neurological sciences and, by courtesy, neurosurgery, at Stanford University. His latest book Behave: The Biology of Humans at Our Best and Worst is available now.

The Joe Rogan Experience. During my day, Joe Rogan Podcasts! By night! All day! Alright. Well, first of all, thanks for doing this. I really appreciate it. I found out about you several years back. I had heard something about toxoplasmosis. Am I saying that right?

Yeah. And I had seen a speech that you had given on it where you were talking about how many people had been infected by this cat parasite. I've had cats my whole life, and I even had feral cats. And I've always wondered, like, I should probably get tested. I'm worried about the result.

Perhaps not. Well, it was just fascinating to me that literally, I mean, what is the number that you estimate in Americans alone that might have been infected? I believe it's on the order of, I'm not sure with Americans, but worldwide it's something like 50% of humans is the best guess. 50% of humans worldwide? Something on that scale. For people who have never heard of this, would you mind explaining what this parasite is and how it affects rats and then cats and then people? Okay, totally bizarre.

So it's this protozoan parasite, Toxoplasma gondii, and it's got one of these weird parasitic lifestyles. The only place on Earth where it could reproduce sexually is in the gut of a cat. I don't know why there are people who know this, but so it reproduces there, comes out in the cat feces, feces are eaten by rodents, and now Toxo's evolutionary challenge is to get that rodent into a cat's stomach. So what Toxo has evolved is this ability, it slowly migrates to the brain of rodents and basically wipes out the innate fear that rodents have of cat smells. Like you take a lab rat who's been like the descendant of lab rats for like a thousand years and never seen a cat and put like a little puddle of cat pee in its cage and the rat's going to go on the other side of the cage. Just hardwired instinctual aversion to cat pheromones

and then put Toxo in a rat and it loses that aversion. And in fact, in a subset of rats, they like the smell. So out in the natural setting, you now go and approach a cat and soon the rodent's inside the cat's stomach and Toxo is completed its life cycle. inside the cat's stomach and toxin was completed its life cycle well i'd heard that it was uh so it's a subset of rats that that actually are gravitated towards it because i've heard it actually rewires them sexually right yes that that's actually work that we did in my lab that it basically crosses some of the circuitry in the brain and hypothalamus so that cat pheromones that used to be activating every alarm circuit in your limbic system in these rodents now instead sort of taps into sexual arousal pathways. And in male rats, when they smell cat pheromones, they increase testosterone production.

So Toxo has just figured out the most brilliant way of doing it. It makes cat pee smell sexy. Is there any understanding at all of the mechanism of how a parasite can figure out how to rewire an animal's sexual reward system, the fear of predators? How does that work? Well, that's something my lab spent a bunch of years on, trying to figure out. I mean, you look at some of these parasites. This taps into this whole world of behavioral manipulation of hosts by parasites. And it turns out they've, like, evolved unbelievably brilliant mechanisms for manipulating hosts for their own benefit. I mean, think about it.

You get rabies, you get a rabid dog, and what that's about is a virus that has affected the nervous system of that dog so that it's now rabid and more likely to bite somebody with viral particles in its saliva, which it now passes on to the next individual. Like you take 10,000 neuroscientists and stick them in a convention on the neurobiology of aggression and rabies knows more about the neural wiring of aggression than we do. Wow. And toxo knows, quotation marks, something about fear and aversion and the neurobiology of attraction. Part of what it seems to involve is toxo somewhere along the way has picked up a gene that is pertinent to the dopamine system in mammals.

Dopamine is this neurotransmitter. It's about pleasure. There's no protozoan parasite for doing years that's had any use for this stuff, except it's part of how toxo seems to be manipulating the reward system in rodents. And then, a couple of years ago, there's a paper showing that in chimpanzees, toxo makes you less afraid of the smell of leopards. Wow. so this appears to be a parasite that just has evolved like this spectacular insight into fear circuitry and attraction circuitry and it's all for its own benefit to wind up in a cat's gut so it's specifically cats like do the chimpanzees still have aversions to snakes and

other things that can kill them yep yeah wow and at one point my lab was full of like Bobcat pee and wolf pee and there's actually like a company you could buy urine from. I don't know why anyone would want it except for us, but they sell urine from, actually what they use it for is you can go spritz it around your garden to scare the deer away. Oh, that makes sense. is you can go spritz it around your garden to scare the deer away if they're coming in eating your stuff so there's i don't know where they get the urine from but it's like come certify it and all of that um and yeah it's remarkably specific so like other have they ever done tests where they test like wolf urine or anything like that around chimps do they have any aversion to that um as far as i know the chimp study has only been with big cat urine but the rodent studies exactly that showing it's a fair specificity the rodents lose a little bit of their general skittishness uh they get a little

bit disinhibited behaviorally so just in general they're out more and more exploratory more likely to get eaten but the most selective lasering effect is they're not scared anymore of cat pheromones now what's fascinating to me is that i've also read that um there was a disproportionate amount of successful soccer teams that are in countries with high rates of infestation of toxoplasma. Okay, that one's new to me, but that sounds like exactly the sort of epidemiological studies that are popping up about humans. Okay, so what about humans? There's two branches of interesting stuff with toxo in humans. One is a literature that's been around for quite some time showing that toxo seems to increase the risk of schizophrenia

there's a higher rate with schizophrenia of individuals who have antibodies against toxo in other words sometime in the past their body was dealing with it, who had cats growing up, whose mother had cats during pregnancy. And like anybody who gets pregnant knows, you immediately get all anxious about cat litter boxes because of the possibility of toxoplasmosis. It can attack the fetal nervous system, do all sorts of damage. And a subtle version of it seems to be a sleeper effect of increasing the risk of schizophrenia. The other realm is toxo-infected humans get subtle changes in personality, neuropsychology, sort of neuropsychological profiles. They get a little bit disinhibited. If you're toxo-infected, you're more likely to die in a car accident involving

reckless speeding. If you're toxo-infected and clinically depressed for the same severity of depression, you're more likely to impulsively kill yourself. In other words, toxo is doing something kind of similar. If you're a rat, one of the hardest wired scary things in the universe out there is the smell of a cat. If you're a human, it's hurtling through space really fast and jumping out of windows and toxo seems to blunt a lot of those effects there.

In the speech that I saw you give, you were talking about your time working in a hospital and that there was a disproportionate amount of motorcycle victims. This was actually something I heard from a clinician an old sort of parasitology

infectious disease doctor who sort of when I was first telling him about this sort of emerging toxin story he had like one of these bolts of memory saying my god I remember back when I was a resident there was this old doctor saying you know if you're ever harvesting all organs from an accident victim I don't know why I don't know why but if it's from somebody who was in a motorcycle accident make sure you check to see if they have toxoplasmosis.

I don't know why, but there's a high rate of that that you find in organs from people who were killed driving motorcycles recklessly. Totally anecdotal, N equals one kind of thing, but nonetheless, this was a guy who studies infectious disease and toxoplasmosis and had not heard about sort of the behavioral findings before and then out of the recesses of his memory so what initially seemed

like okay this is a parasite that's very selectively developed this life cycle between cat stomachs and rodent brains and completing its life cycle. And weird, when it gets into humans, it has some behavioral effects also. That's just kind of evolutionary spillover. But then you see if it's doing something similar between chimps and leopards, suggesting that that life cycle manipulation has been selected for in primates as well. Very strange. It's very strange. And for me, the strangest thing is the certainty with which there's a gazillion viruses and

bacteria and God knows what else out there that manipulate host behavior in ways we just haven't figured out yet. Or we just haven't discovered the particular... Yeah. What does it do to women? Does it have a similar effect? It seems to have less severe effects on neuropsychological profiles of women. Again, the literature on this is pretty scanty in humans,

but it seems to have some similar effects but not as extreme. However, the story now gets a little bit more complicated, and this is actually this fabulous scientist, Ajay Vyas, who's my postdoc, who's now a professor in Singapore, who's continued to study this. Okay, so normally, one of the things animals have evolved to be really good at is picking up signals that somebody else is unhealthy. Like a potential mate is unhealthy, there's sickness behavior, there's very olfactory cues. If you're a rodent, it makes perfect sense. The last thing you want to do is to be mating with somebody who's like

rancid and infectious and rodent equivalents of STDs. So, normally sick animals, parasite-infected animals and such are detected by other rodents and avoided. Toxo does something different. You get a toxo-infected male and now he smells more attractive to female rodents. And when mating, Toxo gets into the sperm and can be transmitted to the female. So suddenly we've got a different story here. We start off with a parasite story where toxo is just ruthlessly exploiting the poor rodents for its own reproductive benefit and its own evolutionary selfish gene well-being. But now instead, it's got elements of, instead of parasitism, symbiosis.

So you're a male rat infected with toxo. Downside, you're more likely to get eaten by a cat. Upside, you're more likely to pass on copies of your genes by increased sexual selection. increased sexual selection. So it might be, in fact, more of a balanced symbiotic relationship between male rats and toxo. You know, more research is needed, blah, blah. It's just like cool sort of biology out there.

It's crazy. And is it transferred sexually with men and women too, as well as with rats? I don't know. I don't think it's been looked at. Oh, wow. That seems like something I would want to look at right away. Yes. What about organ donors?

Other than, again, pure anecdotalism, that one elderly doc somewhere back when saying, watch it when you're getting organs from like people killed motorcycle accidents beyond that i don't know i mean people are looking at it i'm sure but do they even test like say if you got a liver and you know like you needed a liver transplant would they i suspect they do and sort of in the clinical world of people who worry about toxo tox toxo, pregnancy, scary, alarms going off. Toxo, anything else, after an acute period of infection, you have a latent toxoplasma infection. In other words, the agreed upon sort of notion there is toxo has gone latent. It's formed sort of these cysts that are inert and you got nothing to worry about then. but the whole notion that meanwhile up in the nervous system there's effects happening there you know infectious disease people are thinking about

inflammation outside in the body there for them chronic toxin infection is not something you worry about a whole lot but if it's having behavioral effects up there in the nervous system, maybe it is something to worry about. Well, to me, it's unfathomable how this little thing figures out how to hijack a whole body, a whole biological system, and work it to its own desires. It's very hard for me to grasp. Well, if you think of it in terms of, oh, I don't know, Toxo has had like 100,000 more generations to evolve its ways of exploiting mammals than mammals have had ways of fighting it off. What's most remarkable is it turns out this is like a whole world of

parasites that do bizarre manipulative things to their hosts. Most of it's not in the realm of mammals. Instead, there's like some parasitic something or other that gets into barnacles and takes over their reproductive system so that the barnacle digs a hole for them them not the barnacle but the parasite to lay eggs into there's you know the aquatic worm that infects the grasshopper makes it commit suicide exactly that one's bizarre that one's bizarre there's this wasp that gets into cockroaches and takes over it's. I'm fascinated by parasites beyond, but it's just, it's so confusing to me how something,

I mean, obviously you're dealing with hundreds of thousands of generations for it to get to this, this current state, but like how something evolves to be so effective. Yeah. It's just, it's so confusing.

It's remarkable um you know just to flip to the the other end of the spectrum in terms of what like co-evolution between two different species could be like over the last 20 000 years look at what we've done we've taken wolves and we've turned them into these creatures we put halloween costumes on right and like a finding a couple of years ago which like floored me this hormone oxytocin which is totally trendy oxytocin is completely cool mother infant bonding is mediated by oxytocin pair bonding and monogamous species oxytocin makes you more trusting and expressive and generous and economic games and oxytocin has all these pro-social effects within a species but then it turns out that this hormone that has spent the last i don't know 100 million years having mothers

and infants connect to each other emotionally um when you and your beloved dog sit there and stare into each other's eyes, you both secrete oxytocin. And if you pump up oxytocin levels in your dog, it will stare at you longer and you will stare longer back and secrete more oxytocin. This is like an ancient, ancient hormone having to do with mother-infant bonding. And in 20,000 years, which is like a blink of an eye evolutionarily, suddenly we're doing this weird oxytocin tango thing with another species. Another species who we feed and take care of, and they like manipulate

us wildly into like getting them like good, like dessert treat bones and stuff like that and they in turn do all sorts of wondrous stuff for our self-esteem because they like lick us unconditionally and where'd that come from like just 20,000 years and you've like hijacked this ancient neuroendocrinology about like parental behavior and now it's got to do with this weird symbiotic thing we and wolves worked out somewhere back when what does it have any effect on friendship like human beings staring at each other did that does anybody ever tested that I would assume people have looked at that it for example it strengthens monogamous bonds.

And there's a literature by now looking at oxytocin has its effects by binding to an oxytocin receptor. There's a gene for the oxytocin receptor. It comes in a number of variants. And if you have one particular variant that's associated with oxytocin having less effective of an oomph in your nervous system that's associated with less stable relationships so you know none of this stuff is deterministic your your your sex life and your romantic life is not being determined by this one gene like nothing remotely resembling that but that's just part of the mix in there.

I just wonder if that mix applies to platonic friendships, like male bonding and stuff. I wonder if there's, when guys are out having a good time, if they're also getting a good juice of oxytocin. My guess is when you have your basic pathetic male sociality, which is like you talk about sports for five minutes with some guy, and as a result, you're willing to give up your life for him because this is male-male bonding. I bet that's got something to do with oxytocin. Yeah, I mean, it only makes sense. How many of these different factors are there in manipulating human behavior? I mean, this is essentially your specialty, right?

Yeah. Okay, so switching over to this part of the brain the frontal cortex which is just like the coolest part of the brain it's the most recently evolved we've got more of that or it's more complicated than us than any other species what does the frontal cortex do it makes you do the harder thing when it's the right thing to do. Self-control, long-term planning, gratification, postponement, emotional regulation, all this sort of stuff. And frontal cortex, its function is totally amazing how it does this. Okay, so another way of stating that is over and over in life, we come to splits in the road where we've got temptations and we've got impulses and we've got yeah go for

it right now you know you want it and the frontal cortex is critical at that juncture as to whether we like do the inane impulsive self-indulgent thing that we may perhaps regret for the rest of our lives or if you tough it out and do the right. And like what your frontal cortex does at critical junctures is like one of the most consequential pieces in neurobiology we've got. So you ask what kind of things affect how well your frontal cortex is working in that one second where you have to decide

if that person is holding a cell phone or a handgun and do you pull a trigger? Or in that one second where you decide, do you take this thing and run? Or does temptation get resisted? And so what sort of biological things affect what your frontal cortex is doing? How hungry you are, if you're hypoglycemic, how tired you are, if you're in pain. All of those make the frontal cortex work not as well. If you're male, what your testosterone levels are at the time. No surprise, testosterone makes your frontal cortex all sluggish and stupid. What your stress hormone levels were. If you've been traumatized over the previous five months because sustained stress

will atrophy the frontal cortex. But wait, what versions of the number of genes you've got, how much stress hormones you were exposed to from your mother when you were a fetus, how much lead there was in the water when you were a kid, if your ancestors were nomadic pastoralists and developed a culture of honor, what your nutritional status was when you were a kid, and everything in between. All of this coming down to, whoa, there's just biological forces shaping what we're doing to an incredible extent. And it's the exact same story about any other part of the brain, but this is just like one of the most dramatic ones. Oh, a moment of agency and free will and volition, whether or not I'm going to resist this temptation or not.

By age five, for example, a kid's socioeconomic status is already a predictor of how much frontal development there is in this part of the brain. Because if you've been foolish enough in this country to choose the wrong parents to get born into there and you're being raised in poverty, on the average, your stress hormone levels are higher. And as a result of that, on the average, your frontal cortex is thinner and not developing as fast. And on the average, already at age five, you're not as good as on average at the hold out, relieve me, you're going to be glad you held out for this long-term reward thing wow now does toxo have an effect on the frontal cortex um almost certainly that's that's a hot area of research um we were originally hoping to see that oh toxo was just gonna like laser in on

just some key parts of the brain that are absolutely essential to its behavioral effect seems to wind up more widespread so that was sort of makes it a tougher story but in some ways sort of impulsive behavior is either due to a stronger biology of impulsiveness which has much to do with the limbic system, or a weaker biology of, hold on a second, are you sure this is such a great idea? The hold on a second, is this such a great idea, is the realm of the frontal cortex. So that could very readily be half of the equation right there. Wow.

Now, the frontal cortex is not fully online until you're, what, 25? 25. It's a boggling thing. So you just live your life like an ape. Until you're, I mean, you're deep into your adulthood. You're responsible for yourself for over seven years. Yep. Which has some, like, stupefying implications.

And not just for, like, explaining why your freshman roommate was the way he was. Is it uniform with male and women? Yeah. Female development, maturation of the frontal cortex, configures faster in females than in males, of course. But nonetheless, it's this very delayed maturation. And that has to do with what you're talking about with testosterone impeding it? It seems to be a different mechanism there but just in general so compound brain so that says that

the testosterone impedes it and then there's something else as well sure does not help but it's this completely well it's basically the explanation for why adolescents are adolescent they have a brain that's going full blast, especially the dopamine system with reward and sensation seeking and novelty seeking and anticipation, and a frontal cortex that's like half baked at that point and is not very good at controlling impulses. That's why adolescents are the way they are so two sort of really interesting implications with that first one is sort of in the kind of big picture legal implications realm this fact that the frontal cortex is not fully developed till you're in your mid-20s was implicitly the main

driving force around the Supreme Court some years ago saying you can't execute somebody for a crime they did before age 18 and you can't put them behind bars for the rest of life without a chance of parole because their frontal cortex isn't quite there yet. Of course the flaw with that thinking is the presumption that magically on the very morning of your 18th birthday you suddenly have a spanking new frontal cortex that has memorized all those Sunday morning sermons and can get you to do the right thing. But at least the courts have implicitly recognized that brain maturation, parentheses, frontal cortex, is such that adolescent impulse control is not what you see in adults and has to be judged differently. The other issue that sort of fascinates me on a neurobiological level, you know, most of your cortex is doing just fine by the time you're three, four, five years old,

and there's the frontal cortex taking another like 20 years to get there so you say so is the frontal cortex just a tougher construction project than the rest of the brain does it have like fancy type neurons you don't see elsewhere that take amazing wiring or like unique neurotransmitters like what is it just like a tougher construction project is that why you get the delay and you look closely and no it's not it's not implicitly a tougher project you don't get delayed frontal maturation because it's so hard to wire up you get the delay because we've been selected to have the delay you want a frontal cortex that spends a long, long time learning. Okay, how come? Because by definition, if this is the last part of the brain to wire up,

it's the part of the brain that's most sculpted by experience and environment and least constrained by genes. And this is the part of the brain that does social appropriate context learning. And that's incredibly tough stuff like every society every culture on earth you think about it every culture on earth celebrates some types of murder and is horrified and punishes other types some get medals some get damnation some get like simply that one every culture has some sort of strictures against lying yet in some circumstances expect you to have socially appropriate lying in certain

circumstances of protection or so on and every culture does this differently every culture has culture specific mores and situational ethics and things like that. And that's like fancy, complicated stuff that takes a long time to learn. That's what you're doing as an adolescent, as a young adult. You're learning all the subtleties of appropriate behavior. That's your frontal cortex learning, not just how to get you to do the right thing when it's a harder thing to do, but all those complexities of what actually counts as the right thing. And all the things that make us human above all the other primates above all others because we're the species that in some cultures can say we strongly believe in

monogamy and build our theologies around that, yet at the same time have incredibly high rates of people failing to remain monogamous, yet condemn that we have cultures where you're not supposed to lie, yet at some point you have to learn, okay, it's okay to lie in a circumstance of, so tell us, are you harboring those refugees in your attic? No, no, of course not. Situational ethics like that, it takes a very strong frontal cortex to keep you from lying in certain tempting circumstances. But once you decide you're going to lie, it takes a strong frontal cortex to do it right, to do it effectively, because you got to regulate your voice and your facial expressions and where your eyes are looking whoa so this is a part of the brain that's got to incorporate your society's

rules as to when it's okay to lie and in fact this sort of thing that we view is heroic but when it's not okay to lie but once you decide you're going to lie, how to do it effectively. This is like complicated neurobiology. It can't just come with a genetic program that wires it up. It's got to be totally sculpted by learning all those subtleties. Wow. And is there another animal other than humans that does delay reward? Yeah. I mean, the dopamine system, the reward system, the interactions

with the frontal cortex, it's happening in a rodent. Like rodents could learn to master, okay if I press this lever once I get one reward, but if I do two lever presses, if I work twice as hard I get three rewards, whoa that's the way to go it can master that monkeys can master that but it's just implicitly a different thing like a monkey could do a delayed gratification task where it's got to wait a couple of minutes for the reward and it's the exact same neurology as us doing delayed gratification except we do delayed gratification like you study hard to get a good SAT score, to get into a good college, to get into a good grad school, to get a good job, to get into the nursing home of your choice.

We do delayed gratification that takes 60 years. Depending on your theology, we do delayed gratification where the reward's not going to come, supposedly, until the afterlife. So, like, yeah yeah a monkey can have its frontal cortex do delayed gratification for it wow on the scale of minutes and we go and we like do it for 70 years it's we're just in a different league in that regard wow so essentially maybe even some religious rules or some ethical guidelines that we follow could almost be like a scaffolding for the frontal cortex. Absolutely.

The rule of what counts as the right thing and what counts as the harder thing is very, very culture-specific. And that's a tough neurobiological job to master. Do we have any idea when this was due? You said this is the most recent thing developed in humans or the most recent that we understand? Well, it's the most recently evolved part of the brain, which is to say, like lizards' cortex. I mean, it's not much to write home about, but they've got like primitive cortex. It's not until you get to mammals that you start getting fancier cortex that does more abstract stuff and it's not till you get to mammals that you start

seeing the first hints of frontal cortex so you know recently evolved the last 50 to 100 million years so in other words the frontal cortex is like spanking new, and you get to primates, like you get a big frontal cortex, and it's particularly large in apes, and then proportionally it's particularly large or complexly wired in us. Now, I know you spend a lot of time studying baboons, and I listened to that Radiolab podcast that you did where this baboon, did you call it a troop? Yeah.

Baboon troop that was next to the place that was dumping human waste or human garbage. Yeah. And these baboons became accustomed to eating this human garbage, and the unprecedented change in their behavior when the males, the dominant males, got sick from tuberculosis. Yeah. Okay, so, as you said said i've been studying baboons how did you study them by the way like how does that work what do you do oh it's been 33 summers i spent out there going back to a single every year um it it ended about eight

years ago but it had been essentially 33 straight summers wow of like you go back to the same animals and you camp under the same tree and this is in a national park in East Africa and you go back to the same animals and sort of the particular area I've focused my work on over the years is stress and health and what stress does to the brain and and with the baboons it was trying to make sense of what does your social rank and your personality and your patterns of social affiliation have to do with which baboons have the rotten cholesterol levels, which baboons have the high blood pressure, who's healthy, who's not. So these are animals where you go do your basic Jane Goodall scene of just like watching them endlessly and knowing all about their personal lives.

And in addition, I would dart anesthetize the baboons using a blowgun system, which was totally fun to do. But anesthetize them. And when they're down, do basically the same clinical workups you would do on a human. Sort of, okay, how's this guy's immune system working this year how's their you know just working that the last time i was out i had a portable electrocardiogram machine for looking at cardiovascular cardiac function in these guys so you keep them there for a day you do various tests and then you let them go back to their buddies and then you have a sense of how is their bodily function,

their health, their diseases, their stress physiology related to aspects of behavior. For the first 10 years out there, I thought what I had learned was if you want to be a healthy baboon with a minimal number of stress-related diseases and you get a choice in the matter, you want to be high-ranking. It took me about 25 years, and almost certainly that had to do with my having to grow up a little bit on my own, to realize that there's much more interesting stuff going on. If you've got a choice between being a high-ranking baboon or a baboon with a lot of stable, affiliative relationships translated into english friends friends are going to be even better for your health like that's even more protective how often

do you sit and groom with somebody else how often you're sitting in contact how often you're playing with infants turns out that's much more of a buffer for good health than simply what your dominance rank is. So these baboons, they started eating food from a resort and it changed their behavior to the point where they were no longer getting up very early and foraging. They knew when the food was coming, so they just wandered down to this dump and then they would basically essentially fight over dominance of the dump. And a a few strong powerful males had control over that until they got sick great yep so this was the troop next door to mine that had this tourist lodge in their territory and thus had a garbage dump and like national parks everywhere have this issue of having to control wild animals access to so this garbage dump troop as you said taken

to basically just living in the trees above the dump, waddled down each morning just in time for the food junk leftovers from the lodge to be dumped there. And I did a few studies on this troupe. They got high cholesterol levels. They got borderline diabetes. They put on subcutaneous fat. They were eating western style.

Yeah, exactly. they got tooth decay they got different like parasites in their stomachs so they're they're just fine living off of the good life they're like throwing out desserts from this tourist lodge and in my troop a couple of kilometers away i don't know how this works but but in some baboon way, some of my males got word of this feasting going on up there. Like, if they smelled it, I don't know. But it evolved that in the mornings, about half the males from my troop would pick up and run those couple of kilometers to go punch it out with the guys there to get access to some of this garbage. The key thing was that it wasn't random which of my baboons would go over there. So you're a guy from like an outside troop and you show up at this garbage dump and there's 80 baboons like feasting there and you're an outsider.

No one from my troop would like dream of going near the garbage unless he's a big aggressive guy. The other thing is morning is when baboons do most of their socializing stuff. They sit around and they groom and they gossip before they go out and they do the day's foraging. So if you're willing to pick up and instead spend each morning fighting with strangers over garbage, that means you're not very socially affiliated. So in other words, the males from my troop who were going to eat the garbage were the most aggressively socially affiliated guys. So this is going on for a couple of years and then there turns out to be a tuberculosis outbreak among the baboons over there because there was tubercular meat in the lodge and a meat inspector was being bribed and

all sorts of horrifying things. And, you know, a human gets tuberculosis and they can sit around and write thousand page novels about it for the next 10 years while they slowly waste away. TB kills other primates like over the course of weeks. It's like wildfire and non-human primates. So there's an outbreak of TB from the infected meat in this lodge dump, and it basically kills all the baboons in that troop, and it kills all of my baboons who had been going over there every morning for food. So now what you have is half the number of males as usual. So you've got a two-to-one female-to-male ratio, which is pretty atypical for a baboon troop. And the key thing is the baboons who are left

are the nice guys. They're socially affiliated. They're the least aggressive. What's baboon aggression about? You're having a bad day. You find somebody smaller and weaker to take it out on. They weren't dumping on weaker animals. They weren't having displaced aggression. And it turned into, just to be technical here, like a much nicer troop. They had much higher rates of grooming, less aggression, more sitting in contact. Male baboons would groom each other, which you don't see male baboons grooming each other in this troop. They would.

So in and of itself itself that's totally fascinating. So okay, you get rid of 50% of the males who are the jerks and you have a commune there going on. What was most interesting, the thing that just flattened me, was ten years later the troop is still like that. Ten years later all the males who were there during the TB outbreak, who survived it and ushered in sort of the commune, they're long gone. So who are the new males? Male baboons pick up at puberty, they leave their home troop, and they go wandering and join some adult troop somewhere else and spend the rest of their life there, heading up the hierarchy. In other words, by 10 years later, all the males in this troop who were still being less aggressive and more socially affiliative, they had all grown up someplace else in some other troop

and transferred as adolescents into this troop and somehow or other learned, even though they grew up in the normal big bad baboon world out there, somehow they learned, we don't do crap like that here. Cut it out. Wow. And I did a ton of work sort of seeing what that was about. And it takes about six months once these new males show up. For them, they're less subject to resident males dumping on them because there's less of this

displacement aggression females who are getting dumped on less by males and thus are much more relaxed lower stress hormone levels are more willing to be affiliated with them you're some new adolescent male and you show up in your typical baboon troop and it's like 80 days on the average before some female grooms you in this troop it was like three days every because everybody's much more relaxed because no one's being miserable to each other and it turns out you take a jerky adolescent male because these guys were just as jerky as any transfer males were into any of the neighboring troops. And like, you treat them nicer, and they kind of calm down over the next six months. And literally what you had, what social anthropologists would be forced to define as cultural transmission,

non-genetic transmission of a style of behavior from one generation to the next. This was culture being transmitted, a culture of high affiliation and less aggression. And these baboons are essentially living a natural life. They're not getting food from people. Yep. They're just living out in the Serengeti in East Africa and just going about normal baboon life. For me, what was most striking about this is

baboons are as high rates of aggression as you find in any non-human primate. Male dominance, highly hierarchical structured societies. Since the early 60s they've not just metaphorically but they've literally been the textbook example of primates evolved for aggression and male dominance and hierarchy and stratification and all it took was one generation of a radically unique circumstance and you see a pattern of bagoon behavior that had never been seen before so in a sense what we see in human beings we see big differences in cultures in the way people are treated the way

women are treated the way we they cohabitate with each other the way uh you know just whatever uh the community that they live in there's differences in the way we behave but with most primates would you essentially say like most chimpanzees or most bonobos that you can kind of uniformly say bonobos behave this way chimpanzees behave this way is this the only time you've ever seen like a complete variation of the standard behavior of a primate um as far as i know this is the only example of something like this that's been seen but other ecological extremes and you get some radical shifts but in lots of ways this is the biggest cultural shift that anyone has seen in sort of the social milieu of a baboon troop um and for me

what the biggest take-home message of that is exactly what you just honed in on oh these guys are textbook examples of the inevitability of stratification and aggression and no it turns out it's not inevitable it can suddenly flip with some like unique circumstances and be transmitted multi-generationally anyone who could look at humans and say that there's certain inevitabilities to some of the most unpalatable things we do they don't have a leg to stand on yeah if baboons have the behavioral sort of flexibility plasticity built into them just lurking for a unique situation like this and suddenly six months of a different cultural style and you adopt it and pass it on uh again you don't have a leg to stand on to say that certain of the worst things about human culture and behavior is inevitable no we vary so wildly uh from continent to continent that we've kind of gotten

used to it but to see it in in another kind of primate and to see that circumstances can change the way they behave and literally change their entire community to the point where decades later it's like 20 years later they're still the same right is that the case they the culture there went for about 20 years and is it does it dissolve down did it evolve back to normal baboon behavior fortunately it basically ended when the troop sort of moved into the vacuum created by the TB outbreak. And the neighboring troop moved into the lodge area, and they kind of disintegrated as a troop. A lot of them got habituated enough to the humans there to represent the danger.

Game Park Rangers had to kill about half of them. So the troop basically does not exist anymore. But it went on for about 20 years. That's crazy. Well, does that give you hope when it comes to human beings because it seems like it's such a radical shift of the behavior of a a primate without a language yeah that to to see that that's possible that just a shift of circumstance can change the entire behavior pattern of this troop yep i mean sort of the the the easy take-home message is to usher in world peace with humans, just like go give TB to all the aggressive males. But I guess that's not the sort of most obvious take-home message. But I mean, you look at humans change, human cultures change.

The 17th century, like the most terrifying people in Europe, were the Swedes. They spent the whole century rampaging through Europe, and they've now gone more than 200 years since they've had a war. World War I Christmas trees. In 1914, all it took was about four hours of British and German troops fraternizing from across the lines, while they were supposedly doing nothing more than retrieving dead bodies from no man's land between the trenches. And before it was over with, they were praying together and having Christmas dinner together and playing soccer together and exchanging addresses to meet after the war. And where they held out for days at some of those points until officers had to show up and threatened to shoot these guys unless they went back to try to kill each other.

Change can occur very dramatically i mean these days there's entire travel agencies that devote uh that are devoted to vietnam veterans going to vietnam going back for reconciliation ceremonies or going back to foundations that literally build bridges across rivers, help build schools, all of that. What if that could have been conceived of in like 1970? Yeah, humans have an astonishing capacity to change. It's so fascinating when you consider all of the variables that cause a person to be who they are, to behave

who they are, and then them interacting with all these other people who share variables and have unique variables, and that there's so many different factors in what makes a community, a city, a country. It's pretty mind-boggling when you consider all the variables. It's utterly mind-boggling. And just to really get sort of provocative at this point, what one does with all that complexity and with all the biology we haven't discovered yet and all those gaping sort of holes of explanation as to where that behavior comes from is this thing we call uh free will yeah all free will is is the biology we haven't discovered yet

yeah uh sam harris broke my brain talking about free will once where i really believed it was real until he started explaining to me determinism and all the different variables and yeah i mean there is a little bit of something that we have where you're talking about the frontal cortex that allows you to resist things but like why is yours the way it is is the big question right yeah and if like some of it had to do with how stressed your mother was when you were a fetus yeah like how okay like here's just on the level of sort of sensory stuff going on, just the sensory cues we're getting in the world and how that's influencing our behavior. Put up a pair of eyes, a poster with just showing a pair of eyes on a bus stop and people litter less.

Display a pair of eyes on a computer screen and people become more generous in online economic games because it's tapping into being watched. Stick somebody in a room with smelly garbage and they become more socially conservative on questionnaires they're filling out because something just feels viscerally disgusting and that biases us towards deciding

that something that's different is different and wrong. People don't become more conservative about economic issues or geopolitical stuff. They're just more likely to decide that thems who do something different from you, it's not just different, it's wrong because something just feels kind of disgusting because there's smelly garbage in a room one very influential study looking at 5 000 judicial decisions over the course of a year in a parole board system and the single biggest predictor of what decision a judge was going to make if they gave somebody pearl or sent them back to the slammer was how many hours it had been since the judge had eaten a meal.

Wow. Because when you've got higher glucose levels in your bloodstream, your frontal cortex works better because it's a real expensive part of the brain. And when you're hungry, you feel less sympathy. You feel less empathy. People become less generous in economic games and how much would you contribute to this and what sort of a judge has to do there in a situation anytime we judge is do this difficult frontal task of trying to view the world from somebody else's perspective and you're hypoglycemic you haven't eaten in

four hours and it's more likely that your frontal cortex in effect is going to say screw that that's too hard The guy's rotten send him back to jail And what's most amazing is if you had gotten one of those judges two seconds after they made that decision that could most be predicted by the effects of glucose on brain metabolism and asked them So why do you make that decision and they're gonna like be be quoting like enlightenment age philosophers or something and that's just like rationalization running to catch up with the biology that's just rumbling underneath the surface there and influencing our behaviors wow so like maybe one of the best ways we can enhance society is keep people well fed and lower stress yeah um if nothing else like what people have known for decades when we're stressed are like learning and

memory doesn't work that well then people learned we're more likely to be anxious and learn to be afraid of things we don't need to be afraid of and then we learned we're more likely to have horrible judgment and have our frontal cortex not work very well. And the newest realm of that is, and when you're stressed, you're less empathic because it takes a lot of work to try to view the world from somebody else's perspective and worry about their worries instead of your own problems. And if you're in a defensive or worried position, you're most likely to lash out, you're most likely to protect yourself quickly. Yep. And quite literally, a part of the brain that's involved in empathy

doesn't work as well when stress hormone levels are elevated. Now, what about the frontal cortex and actual damage, like damage from car accidents or head trauma? damage like damage from car accidents or head trauma one incredibly interesting contentious area you massively damage somebody's frontal cortex and they will know the difference between right and wrong yet they still cannot regulate their behavior on the most fundamental level. Famous neurological patient in the 1840s, Phineas Gage, he had part of his frontal cortex destroyed in a—he was a foreman of a railroad construction line—a problem with some dynamite, somebody did something wrong, a 13-foot metal rod shot up one of his eyes and out the top

of his head and took his frontal cortex with it landing about 50 feet away and gage who was the sobrietist devout reliable he was the foreman there turns into this disinhibited crass sexually abusive bully afterward who never was able to hold a job again for years afterward because you had taken out of his frontal cortex. And you damage the frontal cortex and you get dysregulation of volitional behavior, which is once again a way of saying people know what their optimal behavior is, the difference between right and wrong, and yet they can't regulate their behavior. Something like, depending on which study you look at, something like 25 to 50 percent of the men on death row in this country have a history of concussive head trauma to the front

of their heads. Wow. And that's a world of like volitional control is not that volitional. Well, that seems to go contrary to the idea of a lobotomy then. Okay, a lobotomy was just, that's great. Lobotomy was just like savaging about the front third of the brain. It was giving the frontal part, but it was also getting limbic emotional systems. What did they do when they did lobotomies? Well, by the time it really got developed, the guy, like one of science's amazing ironies, the guy, a Portuguese neurologist named Agos Moniz, who developed leucotomies,

is what they were originally called, got the Nobel Prize in Physiology and Medicine for this wonderful technique. And then when it hit America as a sort of psychiatric intervention, good American know-how and can-do spirit decided to get a sort of assembly line approach to it. A guy named Walter Freeman pioneered sort of rapid, like, wham-bam frontal lobotomies where you would insert an eye pick through some, an ice pick rather, behind somebody's eyeball, go up through the optic cavity there there and go in there and just scoop around and there you go i mean he had like instructional films in the 50s for how you could do a frontal

lobotomy on like one person every umpteen minutes and just like go through an entire hospital's worth of psychiatric patients in one like devoted afternoon of like calvinist ethic hard work so they were just scrambling it they were scrambling so the neurobiology of like calvinist ethic hard work so they were just scrambling it they were scrambling so the neurobiology of like what you were disconnecting there was it was like virtually random other than you were just making a mess of the front part of the brain so frontal damage instead is a much more selective issue do you shudder when you think about the fact that that was just not even 100 years ago yeah um you know go go go to a medical school library and go eight floors down to the sub sub basement and like go read some of these journals from like 19 aught whatever and like yeah you shudder my god the things they didn't know then.

My God, the damage they could have done then. The damage as to the causes of disease, the causes of psychiatric disorders. My God, some of the things they were doing then. And if you've got a shred of capacity for self-reflection, you then have to sit there and say, well, a hundred years from now, they're going to be looking at our level of knowledge and they'll be saying the same exact thing. What do you think would be the big one?

Do you think it would be antidepressants? Do you think it would be painkillers that they're handing out? What do you think would be the big one that people would be freaking out about today? I think about what we think about in the future. Yeah, but what we're doing now that's... I think it's overwhelmingly going to be, my God, that quaint, medieval, destructive belief they held onto then about human agency and free will. Whoa. They punished people who had brains that couldn't regulate their own behavior. brains that couldn't regulate their own behavior. They punished people who, because of toxin exposure or stress during adolescence, wound up with brains that couldn't control this or that at particular

junctures. And they used words like justice back then. Wow, I can't believe the stuff they did. It was practically like gangs of like gaudierous peasants getting burning torches and going and burning down the whatever's around the medieval castle in terms of senses of the word justice applying to what biology has to do with behavior there's so few people that share this idea that you're having i mean obviously your sense of it is so much more educated than the average person and you understand all the mechanisms behind all these particular behavioral problems that people have, and all these different things can affect the way human beings operate. But most people are not aware of this.

I mean, literally most people. If you had to guess, it might be in the 90% of people haven't really considered all the factors that lead to someone having a brain that would put them in these impulsive decision, terrible decision-making situations? Well, what gives me a little bit of sort of optimism is most people, though, at least in the West, have done that in a couple of realms. realms like 500 years ago if you had an epileptic seizure the smartest most reflective most compassionate like middle ages bleeding hard liberals even would have had an explanation for what caused an epileptic seizure which is you were demonically possessed and the therapeutic intervention was to burn you at the stake and now instead, I don't know, a century or two into having a mindset where instead we make a biological statement. Oh, it's not him, it's his disease. Oh, he's not

demonically possessed. He's got something screwy with his potassium channels in his brain. And once he gets synchronized outbursts every now and then he has a seizure disorder like it's taken us about 500 years to do that one to go from this is a a blasphemous behavior where we know the intervention which is to burn somebody at the state to saying oh it's a biological problem and we even recognize constraints with it if somebody has uncontrolled epilepsy that's treatment resistant, they may not be able to get a driver's license. But you don't sit there and say, yeah, let's have a burning of the driver's licenses and the epileptics. It's about damn time they got what they were. No, it's a realm where words like evil or soul or punishment or justice, it's totally irrelevant. Oh, it's a neurological

disorder. So it's only taken us about 500 years to get to that point so maybe you know we've done that cognitive leap at least once where we recognize there's no victims there though there's no yet well i don't know if somebody most of the time obviously if someone's behind the wheel and they have a seizure and someone dies yeah but we don't think of it as someone doing something. We think of it as they lost control of their body, like literally. Yes. And they're piloting a car, unfortunately, and that's what happens, versus someone committing a crime.

500 years ago, if an epileptic during a seizure with their limbs flailing struck someone, that would have been assault and battery. Because who told them to go, like, sleep with satan that's their own damn fault and it's like it's a ridiculous mindset now there's large parts of the developing world that still has exactly that view of epilepsy but at least in the west like that's an unrecognizably different mindset no no that was not they didn't choose to do that. That was something screwy with their biology. Like we've gotten to that. So I don't know, maybe another 500 years and we're going to be able to do that with maybe half the juries in this country are capable of doing the same thing of saying it's not him.

It's his disease. When you have somebody with paranoid schizophrenia who in a delusional state does something violent, maybe, I don't know, half of teachers in the country are able to incorporate, no, this kid isn't lazy. That's not why they're not learning to read. They have this thing called dyslexia, meaning there's abnormalities, micro- or macromalities in their cortex. And the part having to do with it's not them. It's like, so, you know know we're making a little bit of progress

but so you see you seem optimistic then well optimistic in 500 year time spans when you think it's kind of playing it out in the the right direction just very slowly like when you see these like political debates and and people on television talking about crime and punishment and and none of these factors being discussed, is it incredibly frustrating? It's incredibly frustrating. I mean, they will look back at us and say, my god, the things they thought then, the damage they did then, and all we can do at this point given that we don't know a whole lot of the biology and look at most of this stuff that we've learned about the frontal cortex or oxytocin or genes and we've

learned all of it in the last 50 years, in the last 20 years, in the last 5 years. You look at the distribution of when these papers were published um you know all we could do in the meantime is like have a hell of a lot of humility before we think we understand what the cause is of the behavior especially a behavior that we judge harshly because the odds are we haven't a clue what the actual biology is of what's going on there and we fill in those attributional yawning vacuums with this invention that we call volition and free will has anyone ever used toxo for an excuse or for a defense for a crime i don't there was that twinkie case you remember the twinkie case twink. A damn white, blood sugar levels. That's been used. Severe perimenstrual syndrome has been used successfully in courts of law to mitigate

sentencing of women who committed violent crimes around the time of their period. Having certain variants on genes, this one gene, which unfortunately this variant has gotten the horrible term, the warrior gene, has been used successfully in a couple of courts of law to mitigate sentencing. How have they used that? What is the warrior gene? It's a gene called MAO-alpha, monoamine oxidase alpha. It's got something to do with neurochemistry and something to do with the neurochemistry of aggression. something to do with the neurochemistry of aggression. The gene comes in a couple of different versions, and one particular variant is associated with high rates of antisocial

aggression in humans, if and only if the human was abused during childhood. In other words, the gene is determining absolutely zero, you're getting a gene environment interaction. The absence of an abusive childhood, having this gene variant, has zero impact on this behavior. So, like, ridiculously simplified pseudoscientific interpretations, findings like these, have sort of led even to courts of law saying, oh, well, has that genetic variant. That's inevitably going to scare. So is this similar in a way to, I believe it was India, they used fMRI to determine someone's knowledge of a murder and they convicted the woman and made her guilty of it? Yep, yep.

No Lie MRI is the name of the company in the United States that purports to have the technology well enough that they can tell if you're lying or not. But from what I understand, it was just functional knowledge of the crime yeah which could have been imparted in defending or trying to put together a defense because you're obviously have a lot invested in this crime because you might go to jail for the rest of your life for it yep basically there's no science for that the science is not there yet so it would would never work in America, that case.

Or should not, I should say. Should not and should not work in India. India, yeah. Yeah, that's a case where the science is... So what have they done with this warrior gene? How has someone been exonerated? Oh, where was it? I think it was in a court in Italy

where just sentencing was decreased because the defense made an argument afterwards. Well, genetically predisposed. So, like, that's like... Isn't Italy the place where they charged scientists with not being able to register when an earthquake was coming? Protect an earthquake, yes, by assuring the public there wasn't an earthquake. Yeah, they literally tried them for this.

Yeah, I think... It's my people. Animals. I think the dust is still settling from that one. I think most of those convictions have been overturned. But terrifying that those people had to go to court. Imagine if you're a seismologist and you have to go,

hey, this is not how it works, you assholes. Jesus Christ, I can't tell you when it's coming. You don't think I would be out of the country? What the fuck is wrong with you? Oh, no. My son, the scientist, is like being convicted of murder. So it's essentially in these less informed areas where these things have passed, like the fMRI thing in India and this in Italy, the warrior gene thing. But it's dangerous right yeah I mean you see like be careful what you wish for in terms of

wow it'd be great if people learn more about science way more than a sign like way way more yes a little bit of it is a mighty scary let's see I'm just knowing I need to yeah I know it's 615 should we wrap it up? Sure. Thank you so much. Really, really appreciate it. It was a pleasure. I've been a fan of yours for years. This was a treat for me. I was really looking forward to it.

All right, everybody. This was a short one, but an awesome one. Thank you.