19. Aggression III

Transcription for the video titled "19. Aggression III".


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Intro (00:00)

Stanford University So, back a little bit, still back in the neurobiology, back to the anterior singulate. Remember, anterior singulate again, all that empathy stuff, feeling somebody else's pain, that business is about something metaphorical, something symbolic about pain and empathy is happening. Something people have been speculating about for about ten years now has to do with a class of neurons that have come to be called mirror neurons. Mirror neurons were first identified in motor parts of the cortex, parts that tell you which muscles to move. And these are neurons that don't get excited when you are, for example, moving your arm like this. And they don't get excited if you're watching somebody moving their arm like this, but they do get excited if both of you were doing it at the same time, or closely in time with each other, if they're mirroring each other. So, people took a look at this, and this immediately became an area of a lot of research, and from the first nanosecond, when people were discussing mirror neurons, of course, what they were immediately talking about is, this is some neuronal cellular basis of empathy. Feeling somebody else's pain, that sort of thing, there's got to be mirror neurons in the anterior cingulate that's doing more abstract versions of feeling somebody else's actions and feeling somebody else's feelings, and all that sort of thing totally irresistible. There has not been a paper written on the neurobiology of empathy in the last decade without the word mirror or getting someplace or other in there. Totally cool idea, still not yet demonstrated. Okay, shifting over, covering a little more ground, that business again about sort of storage of very abstract new stuff, symbolic stuff into our clanky old mammalian brains, the notion of having to mix in symbolic metaphorical functions into areas of the brain that do it very literally. What comes through with that is strong support for the argument of someone like hate, that guy the other day arguing that moral reasoning is mostly after the fact, rationalization for moral affect. Mostly what we're having is initial moral affective responses, and that's built around the power of, for example, a symbolic moral failure to cause the same neurons to get excited in your brain that would tell you that you're disgusted with rotten food, the visceralness, the sort of salience of it, the whole notion there being in his work more and more support for it, that an awful lot of the time moral reasoning is coming after the moral decision has been made along the lines of affect. And a lot of the brain imaging work by now is showing evidence for this, and again the strongest sort of evidence is when you go through the list of things, would you eat your pet after it died?

Analysis Of Aggression And Violence

The city of flowers (02:49)

Is incest okay if it's post-reproductive and all the ways in which people say, "I can't tell you why, but it's wrong, that shouldn't be allowed?" And what that is over and over in those cases is a demonstration of the affective moral decision-making coming before the moral reasoning.

Aggression & dopamine (03:21)

It's a really important feature of his work. Okay, backfilling on some neurotransmitter stuff, neurochemistry. I managed to completely forget poor innocent serotonin coming into the picture. What we covered on Wednesday was dopamine and the ability of dopamine to in effect give the frontal cortex the energy to do the emotional regulation stuff. In effect, if what the frontal cortex is saying to all of the limbic system on many occasions is, "Don't do it, don't do it, I wouldn't do that if I were you." What the dopaminergic projections into the frontal cortex are doing is telling the frontal cortex, "Tell the limbic system not to do it because it's going to be amazing if they can hold out down there." The dopamine system in terms of the anticipation of reward. Now switching over to another neurotransmitter that gets lots of attention in this business, serotonin. Before it's over with, we are going to hear about serotonin in coming weeks having to do with a bunch of different psychiatric disorders, but this is serotonin in some frontal-cortical related areas of the brain seeming to have something to do with aggression and impulsive behavior. What's the evidence? First off, the totally correlative stuff. Look at levels of serotonin and animals, experimental animals, in these projection areas that go into the frontal cortex, lower levels of serotonin predicting more impulsive, more aggressive behavior. Consistent finding in the field. Consistent finding when you then switch over to humans and look at something that you cannot do in a human, something not looking at something that you can't do in a human, whatever, you can't look at serotonin levels in somebody's brain because you're not going to slice it out and measure stuff. What that whole literature is about is instead looking at this synthetic pathway, how is serotonin broken down? These two enzymes here, MAO monamine oxidase, this one, broken down into a waste product called 5-hydroxyindolacetic acid. Do not write that down. 5-HIAA, the main point being that in a human, you can't measure levels of this very readily. You measure this in the bloodstream and the cerebral spinal fluid in the urine places like that. In a literature showing that lower levels of serotonin breakdown products are correlated in humans with higher levels of aggression and antisocial behavior. Okay, you should be able to rip that one to shreds within seconds. Number one, this is just correlative and you could very easily imagine horses and carts getting all confused here. The second thing is, remember, when you're measuring neurotransmitter junk in the bloodstream or the urine, you're measuring the junk of all the gazillion different places in the brain where this neurotransmitter is being used for things having nothing to do with aspects of aggression impulsivity, it's really hard to tell anything. Nonetheless, the animal literature has been pretty consistent with this. So back to correlation, which is causing which, which is causing which, then you could do the animal studies showing that when you manipulate serotonin levels in something like a rat or a primate, you drive down serotonin levels in the frontal cortical region and you get more aggressive behavior. You get more impulsivity. So evidence for that they're actually being causal. Something similar or a building block of that, studies that have been done in humans, you don't slice somebody's head open and measure their serotonin levels, but instead in this case, you give a drug which for a short period will mimic serotonin. And it will mimic serotonin the way serotonin interacts with the receptors in the frontal cortex. You're buzzing serotonin pathways and those individuals in the frontal cortex, what do you wind up seeing increased metabolism in the frontal cortex? Serotonin stimulates frontal metabolism except in individuals with a history of antisocial violence. What's that beginning to suggest? Part of what serotonin is doing is joining with dopamine to stimulate the frontal cortex, get the, I wouldn't do that if I were you really, really hold on, don't do it. Pathways down to the limbic system and part of the evidence we're seeing violence sociopaths having lower than normal metabolic rates in the frontal cortex. Some of these pieces begin to come together. So a lot is relevant in terms of levels of this. Immediately one starts thinking genes, genes related to the various types of serotonin receptors, genes related to the enzymes that make serotonin that break it down, and there's a literature that's emerging on that one. First off, it is a really tough literature to make sense of. Okay, as follows, suppose you are studying some population of people who are very aggressive and you're measuring this breakdown product in their bloodstream and you see there's very low levels of the stuff.

Serotonin & aggression (08:27)

Okay, so how do you interpret that? You believe that low levels of serotonin give rise to aggression. So what's your interpretation? Okay, low levels of this because you're not making much serotonin. If you're not making much serotonin, you're not getting much serotonin breakdown products support for the idea that aggression is caused by too little serotonin. Suppose instead you like the idea of too much serotonin causing aggression, what would you then say? Well suppose there's a mutation in one of these enzymes that's supposed to break down serotonin and because of the mutation that doesn't, what's going to happen serotonin doesn't get broken down. It's levels build up and thus you'll see low levels of that. In other words, the same exact finding can tell either elevated or lower than normal levels, completely uninterpretable when you're trying to make sense of what's happening in an organism like a human where you can't actually measure it this step. So there could be low levels because there's low levels of everything or there could be low levels because thanks to a blockade here, the levels of this are building up totally impossible to separate those out. And some of the studies in the field have really strongly voted for one type of conclusion based on human studies measuring that stuff where it simply can't be done. Okay, how about the genetics though? What you see are differences in variants of the gene, that's the critical one for making serotonin. Basically concept, if you're not a biochem type, if there's a couple of steps needed to make something and one step is really, really important. Basically like if this first step occurs, you're guaranteed that the second one will and the first step is the one that's a little bit iffy, that would be referred to as the first step. And referred to as the rate limiting step in the pathway, the rate limiting enzyme, this enzyme triptophan hydroxylase is the rate limiting step in the synthesis of serotonin. And by now, there is a literature showing variants on triptophan hydroxylase in people, variants in non-human primates that begin to correlate a bit with how much of this, how much of aggression, not big effects. In the statistics lecture, the findings are there, they're not big effects though. Meanwhile, at the other end, people have been looking at genetic variants on these guys and that literature is coming through also, different variants that appear to have different levels of activity correlated with different levels of aggression, different levels of breakdown products, so that's out there as well. But immediately, we've got something going straight back to four different earlier lectures, the point being made over and over a graph by now where you know exactly where this one is heading, if I can get that right ink, which is variants on this MAO gene, this monomine oxidase, it comes in two different flavors and what you've got is in terms of how they function, one of them should be predisposing towards more serotonin signaling than the other. And thus, you would predict that the one that predisposes you towards less serotonin signaling in the frontal cortex should be associated with higher levels of aggression.

Violence & MAO-Action (12:06)

Thus, we go back to that same exact study, that same group that did the study looking at the interaction between depression, serotonin transporter gene, all of that, looking at those data. Now, what they were asking was, by age 25 or so, what was the incidence of anti-social violent behavior in this population of 17,000 kids and what does that have to do with which variant of MAO they had, and it's the exact same punchline by now. This is the depression gene environment stress figure, it's superimposable with this, it's the exact same punchline. Having the bad version of MAO-amine oxidase gene does not increase your risk of anti-social violent behavior. Having the bad version of the gene and getting brought up in environment with abuse and vastly increased likelihood, and what they showed in there was the number of times of major physical abuse. During childhood, the more that was the case, the more there was an interaction here. Having the good version, growing up in a more abusive setting, yes, it increases the odds of anti-social behavior. Not a big effect though. What do we got here, yet another gene environment interaction? By now, you should be utterly unwilling to say whether any gene does anything here outside the context of saying in what sort of setting with what sort of background, huge interaction here. So giving a sense here of where serotonin is fitting into it. Next, next piece of neurochemistry that's relevant, and this is not a neurotransmitter, but this is a neurochemical that occasionally gets put into the nervous system, which is alcohol. Alcohol, what does alcohol do first to neurons on sort of a nuts and bolts level, is alcohol a mimicker of any particular neurotransmitter?

Alcohol (13:59)

No. Does alcohol bind to any particular class of neurotransmitter receptor? No, not that either. Alcohol seems to have some remarkably nonspecific effects in terms of how cells function. All one could say at this point is alcohol is not equal to it's kind of working like this neurotransmitter, or that enzyme, or that it's not that clean. It is a messy drug with lots of effects in the brain. So what does alcohol have to do with aggression? Everybody knows the answer to that, which is alcohol increases levels of aggression. Everybody knows this. Everybody knows this, and the guy who gets a couple of drinks under his belt and is flinging people out the bar soon afterward, alcohol increases aggression. What you find in fact is there is no significant relationship between the two. A huge literature examining this by now. And what you see instead is one of our if-then-contingent themes here, over and over, you're getting this sort of thing coming up. Alcohol does not cause people to be aggressive. Alcohol causes people who already are aggressive to become more aggressive. Alcohol causes people who are unaggressive to become more inhibited. What alcohol does is merely magnify the pre-existing social tendencies. This theme over and over again, that's exactly what testosterone was doing two days ago. Testosterone does not make number three ranking. Recis monkey start attacking number two and number one. It makes him absolutely torture numbers four and five. Testosterone does not create aggression. It amplifies pre-existing social patterns to her. That's our remove the testosterone and aggression doesn't go down to zero percent interaction with social history. Same exact theme again. Alcohol does not cause aggression. It amplifies aggressiveness in people who already are aggressive.

Cultural Amplification of Aggression Seeing other Peoples Bad Behavior (15:56)

Along with that, sort of as a confounding factor, we have this problem that everybody knows that alcohol makes you more aggressive. What has also been shown in studies is that if you tell people that you have just raised their blood alcohol levels infusing in other alcohol or infusing in saline, and what you see is when people believe their blood alcohol levels have risen, they become more aggressive. What is alcohol about? Alcohol allows you to give voice to those pre-existing social tendencies towards aggression. Modifier over and over again this sort of theme. This has been studied in all sorts of contexts. One really interesting domain. I've been people who anthropologists who basically study how people in different cultures learn to get drunk. Okay, that's kind of interesting. That must be an interesting thing to spend your career on. What is this about? Looking at one of the people who does this work, looking at this whole issue of populations that did not have a prior history of heavy alcohol use before some explicit transitional event. What that usually translates that into is Polynesian islands that did not have much alcohol before. They were touched by the West during World War II with alcohol brought in heavily after that. The question becomes what are people's behaviors like, and these cultures as they are first having a culture of people drinking to excess. The answer is it depends. It depends on the people who were teaching you to drink. What you see is an interaction between the type of colonial power that controlled the island at the time. What people did, and you would see in British controlled islands, American controlled islands, people would start realizing that you're supposed to be aggressive and become more violent when you're drunk. Meanwhile, over in French Tahiti, people get drunk and they all sleep with each other. Aha, it's cultural context-specific sort of thing, this shown over and over again. Okay, so a little bit on the neurochemistry here. We then began working our way left, looking first at hormonal regulation, the short-term hormonal effects, looking at testosterone. Let's also briefly go to the other side around the time point, the acute environmental releases. Aggression as our fixed action pattern, what are some of the releasing stimuli for aggression? Some of the most reliable ones are ones that always, always demand you to interview an animal in some language across different species, just as with sexual behavior released in stimuli. Some species become aggressive in response to smells, to sounds, to sights, to our whole array with this. Here's one version, here's a species of ant that gets aggressive in response to vibration. And these are ants living in East Africa that have a symbiotic relationship with trees there, acacia trees. And what happens is the acacia trees grow these little sort of igloo bubbly spheroid things on their branches, which have holes in them, and which provide perfect living environments for the ants.

Anthropological Questions with Animals (19:06)

So acacia trees are giving ants a home, and what the ants do in return is they protect the acacia tree from herbivores. Herbivores eating their leaves, what happens along comes a giraffe and begins to chew, and it breaks a branch, and the vibration causes all of these ants to come pouring out and bite the giraffe's lips, at which point the giraffe goes to a different tree. So we see in that case, what's the releasing stimulus? Go and shake a branch, and you suddenly have 4,000 ants angry at you, all these deals again, and again interviewing an animal in its own language. So what are some of the reliable releasing stimuli in humans? Same theme as with the sexual behavior. We don't have any auditory stimuli that automatically trigger aggression. We don't have any olfactory ones. We don't have any. We've got some subliminal ones. Remember that study mentioned a few weeks back, take sweat from someone who is frightened, as opposed to the same amount of sweat from someone who's been happily exercising, that was that deal of swabbing the armpits of people jumping out of airplanes, take sweat from someone who is frightened, and subliminal exposure to it, the amygdala activates. So we're not completely free of sensory stuff, but we're not triggered in any sort of way that is dramatic as in other species. So what sort of sensory multisensory, multimodal sort of things trigger aggression? Number one, most reliable one is pain. Make an organism feel pained, and you have greatly increased its likelihood of turning around and biting the closest thing to it. So pain as a trigger for it. Frustration as a trigger. Take a rat, train it, to press a lever ten times, it gets its food, ten times it gets its food, ten times it doesn't get its food, ten times you're not giving it its food, get the rat good and frustrated, and with great reliability, if there's another rat sitting there, it's going to spin around and bite it. So displacement aggression, being driven there by frustration, by pain, things of that sort, and what's really depressing is if you are a rat or a primate and you are sitting there, being frustrated by not getting a reward and your glucocorticoid levels have risen, go and bite somebody else, and your glucocorticoid levels will go down. And there we describe a very depressing feature about our social world.

Frustration: Idea (21:27)

Displacing aggression on somebody else in species after species is stress reducing. So triggers. Triggers for that. Great example of this and a remarkable one back to that business from a couple of weeks ago, that alternative mating strategy of orangutan males, that business after hearing all that heartwarming alternative strategy stuff of male baboons forming friendships with females. Meanwhile, the alternative strategy with orangutan males, being something that absolutely fits all the definitions of rape, well, do you see anything like that in some other primate species? And you see it every now and then among male baboons. Again, defined as forced sex with a female who actively attempts to get away and actively attempts to resist. What you see under that, it's a redefinition, is every now and then it will happen in baboons. What is the circumstance? I've seen it three times over the years. Other people have seen it occasionally as well. It's always the exact same circumstance. It is the number one male on the day or the day after that he has just been dumped out of his alpha position. And most of the time the animal goes and mopes somewhere else. Most of the time the animal mopes and then finds somebody smaller to beat up on. The only times I've seen this over all these years, that was exactly the circumstance. Frustration, aggression, displacement. Very, very familiar. When we get to some more environmental factors later on some of the big ones, what we will deal with in this context is the relationship between why is it that when the economy gets bad, violence goes up? Why does poverty bleed violence? And this is consistently the case. Why is that occurring? Some framing theoretically within the context of frustration and pain and stress are really reliable predictors of aggressive behavior.

Calhouns Rat testosterone study (23:34)

But again, it's the same theme as with alcohol. Pain makes organisms that are already predisposed towards being aggressive, more aggressive. It does not do so uniformly across the board. Frustration, the same exact thing. Once again we have something modulating, amplifying, blunting, damping, all this sort of theme again and again, some other factor there. Another example of this, another environmental trigger and study this subject somewhere in the 1950s or so and the top thing that you would get on the list in terms of environmental releases for aggression would be overcrowding. This was a whole literature that emerged at the time. A psychologist named Calhoun, John Calhoun, started this whole field. And what he would do was take a bunch of rats living in the enclosure of a certain size and go about observing them and they're going about their rat business and now put all of them into a much smaller space, a higher density, crowd them. And what he reported was aggression explodes at that point. Aggression goes through the roof, crowding causing aggression. The two factoids, or rather the one factoid that everybody learned from that literature for decades afterward from the scientific American papers was violence would go up to the point that rats would start killing and cannibalizing each other. Urban crowding, making our next generation of cannibals, which is exactly what an awful lot of sociologists were off running with, not to mention various southern senators who talked about the menace of inner city population density and spawning violence because overcrowding causes aggression. Whole literature, and it took a number of years until people started looking a little bit closer at the animals. And on the average, the rate of aggression does not change with crowding. You could probably fill in the next sentence by now. What you see instead is animals that are already aggressive become more aggressive when you crowd them. Animals that are subordinate and unaggressive become even more weak and withdrawn. What these early generations of studies were doing wrong was folks sitting there just looking for the exciting stuff. Oh my God, we just saw a rat cannibalize another one. I sure never saw that with a big enclosure. The actual quantitative rates of aggression do not go up with crowding. Aggressive individuals become more aggressive than. And we readily can fit that into scenarios of frustration, displacement, that kind of thing. Okay, now switching back to where we started the other day, back to hormones, the short term hormonal exposure, and where we had started with short term, not the hormonal exposure back when you were fetus, but in the last minute, in the last hour, the last couple of days, where we started, of course, with testosterone. And to summarize that again, it is the same punchline as with testosterone and sexual behavior. Testosterone is required for the normal range of aggressive behavior in every species looked at. When you castrate males, levels of aggression go down. Just as critically, levels of aggression do not go down to zero. Very critically there, the more prior social experience with aggression, the more it is maintained after castration. Replace the testosterone, 10% of normal levels, 100%, 200%, all of them do the exact same thing. The brain is sensitive to testosterone, but it's not sensitive to small little differences in it. So, no individual who is more aggressive than the person sitting next to them, there is no way it can ever be attributed to differences in testosterone levels in the normal healthy range. Back to the same qualifier from the sex lectures, now takes someone who, instead of having 200% of the normal levels, twice the normal levels, they have 10-fold higher levels, higher than the body ever normally sees because they're abusing anabolic steroids, and their levels of aggression do indeed go up. But with the normal range, you've got to have testosterone, but it is necessary, but not sufficient for normal levels. The brain is not sensitive to small little differences, and it is overwhelmingly modulatory.

Testosterones role in competition (27:55)

That same business again, number three in the hierarchy, stoked on testosterone, attacks four and five more, doesn't bother with two and one, exaggerating pre-existing tendencies. Testosterone shortening the lag time between action potentials in the amygdala, if and only if the amygdala has gotten excited and passing on aggressive messages, testosterone amplifies it, testosterone not as causing, but as modulating, that same theme again and again. Finally, towards the end of that, we heard about that amazing example of hyenas in their sex reversal system, one final interesting feature of it, which is we live within 30 miles of the world's only research colony of hyenas who live up in the Berkeley hills, and if the wind is just right, you can hear them whooping in downtown Berkeley at night on occasion, and God knows how many religions that has spawned over there, but they've got this hyena colony there, and these were hyenas that were brought over as pups from East Africa, from Kenya, as part of studying this weird sexual reversal system. Hyenas turn out to be models for a whole bunch of gynecological disorders, having to do with the elevated testosterone levels in the females, all of that, they've now gone through about 20 years in generations, but the very first generation they had raised a critical issue. Back to the other day, hyenas social systems, females are dominant to males, females are more aggressive than males, females have higher testosterone levels. So the question becomes, you've got a whole bunch of hyenas that were brought over as pups, raised without mothers, raised in something other than a normal hyena clan of watching adults, they're all growing up as pups together without adult models, are females going to still wind up being more aggressive than males. And what they saw was, yes indeed, females had the same normal higher testosterone levels, as you would find in wild hyenas, the same weirdo genitals, all of that, and females were socially dominant. Whoa, hormones and bizarre fake scrotums as destiny, but what they saw was, it took years for the dominant system to emerge with the females dominating, it took far longer, what's that telling us about normal hyenas out there, it's a mixture of, you having lots of testosterone on board and its physiological consequences, and you getting to watch mom terrorizing the males in the neighborhood. So once again, a combination between social factors and econ modulators, they eventually got to a classic female dominated social system, it took them a lot longer though. Next, next hormone, hormones to look at, estrogen, progesterone.

Hormones and hunting (30:44)

Back to, no, we're not going to look at that yet, hold on, stop, all of you. Next, what we look at are testosterone levels and females, oh yes, that again. Same exact thing as from the sex lecture, substituted from there, females generate certain levels of testosterone of related androgens. From the adrenal gland, adrenal androgens, maybe 5% of the levels you see in males, and what we saw last week is female proceptive sexual behavior is dependent on testosterone. Same exact deal, take out the adrenals of a woman, testosterone levels drop down to zero at that point, and levels of sexual libido, proceptivity go down, not all the way down, depends on how much prior social experience, same song and dance, and same song and dance here. Aggression, aggression in females of various species is amplified by the adrenal androgens, those low levels, castrate goes down, not all the way down, same exact deal again, it is modulatory in females as well as in males. Now, leaping to estrogen and progesterone, what's up with them in terms of aggression? And we had first hints of it from the very first lecture that business that a disproportionate share of female violence is carried out by women in their perimenstral period, the whole notion of perimenstral syndrome increasing aggression. This has been around for a long time, and this holds up in some criminology studies, though what you see here, of course, is a gazillion different ways of interpreting it. First possible interpretation. All we're looking at here is culture. Culture that decides that menstruation is a state that you are unhygienic and need to be separated from everybody else, and great novels about red tents and sort of cultural values on it. So, of course, behavior changes dramatically at that time with a peripheralization, a stigmatization, and culture after culture, blah, blah. Okay, cross-cultural argument.

Testosterone and aggression in yarn (32:52)

Then there's a personality argument that a lot of people do, looking at the literature, the relationship between increased aggressiveness around the perimenstral period. Again, notice I'm not saying premenstral. What the literature shows is a couple of days after, just as much as a couple of days for, so perimenstral. Personality differences explaining that. Then there are the marvelous psychodynamic psychoanalysts who've been let loose at that for years, and what they come up with, this is one of the great ridiculous soundbites that aggression goes up in women around the time they are menstruating, because this evidence that they are fertile, but have gone another cycle without getting pregnant. Throws them into the conflict, the conflict between, get this, this could go on like a doily in the kitchen, the conflict between being productive and reproductive. Oh, should I function in society or should be I be off having babies like female hyenas, and oh, that's what it's about. It's this deep psychoanalytic conflict and evidence that yet again you have passed up the chance to be a mother in reproductive, so you're going to be in a pissy mood. Okay, so that's a more psychodynamic theory, and that one has been around in the literature forever. But back to the biological one. Biological one. So what sort of evidence is it for?

Aggression Theories And Behaviorism

Menstruation as a high testosterone environment (34:14)

For that. Okay, so what we got here, let's switch from our deal from previously, so now we've got menstruation, day 28 coming right in the middle there, and let us look at this record. Here is a female, someone who you've been observing, and you've been observing in fact for a couple of years, and you keep track of any time they do something aggressive. And what you see after you've got 20 cycles worth of data is the likelihood of it occurring. Does something like that? Okay, that's the perimenstral irritability, that's a disproportionate share of women in prison for violent acts, that's all of that. So what do you make of it when told that this is precisely the profile you see in a female baboon? Well, she's probably not getting bummed out every time she menstruates and wonders whether she really should be holding off having babies until she gets to be a partner in the law firm. What you see there is none of the cultural stuff, none of the psychodynamic stuff, none of these psychosomatic stuff, another realm of explanation, you see something close to the same exact thing in female baboons. So that, and for my money, argues that there's some major biology going on there amid possibly relevant cultural factors, possibly relevant in terms of there always being an argument in a certain school of anthropologists for some decades that you don't see people. You don't see perimenstral shifts in behavior in cultures that are more free about bodies and more sexually uninhibited and presumably this tells you that something about baboon sexual inhibitions, there's not a whole lot of evidence for that. Perimenstral mood shifts is pretty universal across human cultures and you see the same exact thing in a female baboon. So we've got some biology going on there for my money. Nonetheless, you don't have only biology because there are all sorts of psychological factors. One study showing things for example, like if you tell a woman that she is one day before having her period and I'm not exactly sure how this one works, let alone the human subjects permission, but this was a study done some decades ago, women become more irritable. Okay, so a self-fulfilling component. Tell someone that they are going to have their period the next day and their male significant other becomes more irritable. Irritability among men who have significant other women peaks around the time that she is menstruate. Whoa, we've got either some sort of viral and infectious intersectional thing happening here or we've got strong components having nothing to do with the biology. This one in addition studies showing that yes, there is this mood fluctuation. On the average, there is a larger fluctuation in mood affect when you compare weekend versus weekday. In particular, Friday, Saturday versus Monday, Tuesday, bigger fluctuation than the mood changes you see typically in women around the time of their period. So we've got some biology here, but nonetheless there's other stuff going on as well. So what about the biology? One thing that immediately comes up is this issue that okay, peri-menstrual periods, mood shifts there are not purely about aggression and irritability. They are also about depression and social withdrawal. That's the time of cycle when women are most likely to have a depressive episode. Very, very different scenario there. So what's up with that? You begin to get a hint of this looking at the baboons. What you see is this is the profile you would see in a high ranking female baboon. Look at a low ranking female and there's no particular change. Look instead at a measure of how far away she stays from everyone else and it does something like that. In other words, if you are a low ranking female baboon, you don't have the option to be irritable to somebody else and dump on them. You instead become more socially withdrawn, do less grooming. So an interaction between place and society, all of that. So the biology now. Estrogen, progesterone. Lots of evidence that their levels and in particular their ratio is critical to what is going on here. Massive changes in the levels of both of these hormones around the time of one's period and does not take a whole lot for the ratios thus to become very, very skewed. Back to the advanced endocrinology stuff, the fact that parts of your brain are not just measuring the levels of one hormone or another, but the ratio of the two. That seems to be pertinent. What the evidence suggests is in one subset of women with severe perimenstrual syndrome, and that's about 10% of the population, in one subset of those individuals, what seems to be the problem is too much of a drop of progesterone around the time of your period. So what's the neurochemistry of that? Okay, quick memory from a few weeks ago. What's one of the unlikely things that progesterone does? Yeah, the GABA receptor stuff. Progesterone, by way of often this metabolite, this sort of breakdown product of it, progesterone being able to bind to the receptor for GABA at a minor tranquilizer binding site, just like where benzodiazepines like valium bind to. Progesterone as decreasing anxiety, progesterone as mildly sedative, that's one of the interpretations that's given for what a more than normally rapid drop of progesterone might have to do with PMS. Another subgroup of women appear to have an atypically large drop in levels of opioids, endogenous opioids around the time here. Normally there are levels of beta and dorphin, a neurotransmitter/hormone with all sorts of nice effects on mood and things of that sort, and levels tend to go down around this point, a subset of women with severe PMS where the marker there appears to be. A particularly fast drop of opioid, beta, and dorphin levels at the time. So just the first bits of hints of the endocrinology of what that is about. Final hormones. Final hormones, glucocorticoids, epinephrine, nurpinephrine, glucocorticoids, sympathetic nervous system, and it's the same exact deal as two days ago, looking at the fact that those midbrain, hindbrain areas get activated during an aggressive act. Ooh, does that teach us something about aggression? Not in the slightest. What you have instead is the non-specificity. Levels of glucocorticoids will go up roughly equally. Whether you are running for your life or running in rage or running in joy, that whole deal again, sympathetic arousal, it's non-specific. And back to that sound bite from two days ago, the opposite of love is not hate. The opposite of love is indifference. And endocrinologically, this is the case again.

Corticotropin Hypothalamic-Pituitary Adrenal Axis (41:45)

One interesting piece in the glucocorticoid and sympathetic nervous system domain. Take somebody and poke their finger with a pin or make them physically uncomfortable or something painful, and they activate the sympathetic nervous system. This is part of their mild stress response, the early stages of it. One class of people where this doesn't work anywhere near as much, sociopaths. And by now a large literature showing elevated pain thresholds in people with sociopathic violent disorders of behavior, elevated pain thresholds, and less sympathetic nervous system responsiveness to pain. And you should be able to go off and running with that one easily insofar as metaphorically what empathy is about is feeling somebody else's pain. If your own pain system is on the pretty insensitive side, that is certainly going to have an impact there. That's a very consistent finding. Okay, so what we are ready for now is switching over to longer term environmental ideas about aggression. Why do I keep pretending as if the chart is here? Here, we've now moved over to here, shifting from environmental triggers not something painful five seconds ago. Not, I was expecting you get this food helled after pressing the lever 20 times, and I didn't get the lever I am frustrated, not a minute's worth of environmental releases, but instead, general pictures of what environment has to do with aggression. Some of the broad theories that have come out over the years.

5 biological theories of aggression (43:21)

Okay, let's take a five minute break before that. To quickly go through this deal again, so you got amino acid precursor, tryptophan, that's your building block for making serotonin, key enzyme coded for by a gene, it's a protein, key enzyme that turns it into the first step, and then this enzyme there's always a ton around it automatically gets turned into serotonin. So now you have serotonin, serotonin will do its thing by way of binding to serotonin receptors, and at some point serotonin will be broken down into this waste product. So a gene coding for this protein, a gene coding for this one, which we're not interested in, a gene, a bunch of genes coding for the receptors, and genes coding for these two enzymes. And the whole point there being that there's different versions of these genes for the synthetic enzymes, for the degradate of enzymes, for the receptors, and thus beginning to look at whether that predicts differences in levels of aggressive behavior. So that's what that was about. In addition, was just told a great story about somebody who was under tremendous duress to supply alcohol for her younger 16 year old sister and friends at a sweet 16 party, and decided no way is this happening, and thus bought a bunch of bottles of something or other and took the labels off and put other labels on. And before you knew it, you had a whole bunch of 16 year olds acting just asinine and claiming to be drunk beyond words and yes, social modulation of very, very frequently seen. And hopefully some of you have taken part in experiments like that to yourselves over the years, or may force that one off on someone else. Okay, so now pushing over towards some of the broad theories about environmental triggers for aggression, and no surprise, theories are a dime a dozen, all sorts of theorists over the years, and some of which occasionally feel obliged to actually go see if there's data supporting it. But what I'll just touch on briefly are three very broadly different schools of thinking about environmental factors in aggression.

The surround: Gate Theory of Human Aggession (45:39)

The first school is one that says environment is irrelevant, and you can bet how much I'm going to like that here in the coming minutes, and who is the main advocate of that, our ever reliable friend, Heronazi Conrad Lorenz. Conrad Lorenz, after he had gotten out of his prison camp after World War II for being a Nazi propaganda, then he sort of dusted himself off and got his anthology empire going again, and remarkably was forgiven by the other elder fathers of ethos. And he's the one who led the move to make sure that Conrad Lorenz was welcomed back in the community, even though he was an unrepentant Nazi swine. But so after Conrad Lorenz came out, in the early 60s he wrote a book which was one of the most influential anthropology books of all time, a book called On Aggression. And that was the coffee table book for half a decade. That was the book that people had book clubs about if they were intellectuals. On Aggression had a huge influence on people's thinking at the time. And what was Lorenz's basic premise as to what were the environmental components of aggression, what was aggression about, it was exactly the book you would expect to be written by an unrepentant Nazi. Because his theme was just following biological orders. In Lorenz's view, on his view as to what aggression is about, it is inevitable. There is no environmental requirement. Aggression is universal and inevitable. Famous quote of his that he gave, for example, near his death in the 1970s to Newsweek, there is no love without hate. Wow, he must have been a great father. But what you see is a whole premise built on that. A number of the notions, the basic themes that ran through the book. Number one, aggression is universal. It is there in all individuals. Number two, what he called his hydraulic model of aggression. And if this sounds silly, you should actually go see the book because he had actual diagrams of like pseudo toilet bowl plumbing stuff telling us how aggression works as follows. There is some aggression toilet bowl water tank which is slowly filling up with water. And the deal is that the higher the levels of water get, the higher the aggressive drive, the less of an environmental trigger it takes to provoke the aggression to come out. The higher the levels, the more easily a releasing stimulus will trigger fixed action patterns of aggression. Intrinsic in his model also and explicitly stated was eventually his toilet bowl fills up with enough, actually it is not the toilet bowl, it is the tank. The tank fills up with enough water that it begins to dribble over the top and thus you get spontaneous aggression. His model was with the passage of time the longer it has been since an organism has been aggressive, the less of an environmental release is needed to provoke the aggression until it is ultimately spontaneous. The third piece of his model was just like a toilet bowl, again, which is when you have an aggressive act, you have just emptied out the tank, you deplete the aggressive drive, you deplete it so that it resets the system. Starting a refractory period, that aggression decreases the likelihood of aggression occurring immediately afterward. This was the Lorenzian model, which was enormously, enormously influential and everybody learned about this in intro and through the 1960s and it would take you about two seconds to shred this one. Okay, how many of you have ever murdered anyone? Okay, you never know, people are kind of drowsy, checking their emails and suddenly confess, okay, how many of you plan to murder somebody? Yes, we are like the most dangerously aggressive species on this planet and the vast majority of us will never have a physical fight with somebody since we left seventh grade or so, aggression is not universal, aggression is not inevitable. And aggression is not sublimated into psychological processes, which thus can pass a support for this model. The final thing that does it in is aggression is not self-depleting, aggression is self-reinforcing. And all you have to do is look at the crowd contagion, the emotional contagion that occurs in soccer stadiums when people start fighting, crowd violence, all of that. Aggression is not self-depleting and resetting the clock. Aggression stimulates more aggression. Aggression legitimizes it, it habituates you to it, it is not fitting Lorenz's model at all. Meanwhile, on the other end of the block was a very, very different sort of view and this is one that permeates a lot of thinking in the field and this is one built around the notion that aggression is ultimately all about frustration. It is about frustration, pain, stress, fear, anxiety, and this was a view very heavily pushed by Soviet researchers in the period of the Soviet Union, a very Marxist view, because essentially what you conclude at the end is this theme I keep bringing up every time pointing out that the amygdala has something to do with both aggression and fear that in a world in which no amygdala and neuron need have an action potential out of fear, there's not going to be aggression. So this is the extreme version of the frustration displacement model and what is emphasized and that is a lot of data. You look at, for example, when levels of unemployment go up, levels of spousal abuse go up, levels of child abuse go up. When the economy gets bad, the same exact thing. Laboratory animals shock a rat, it will bite the one sitting next to it, all of these versions of displacement aggression. In a baboon, for true, for example, almost 50% of aggression is displacement aggression after somebody loses a fight or loses access to the resource. Almost certainly this begins to explain two really, really depressing things about unequal societies. First one being that the poorer you are, the more likely you are to be violent, the more likely you are to commit some sort of criminal violence, and when the economy gets bad, the rates of that get worse, it gets more skewed, and the other ironic piece of all of that is that when crime goes up in lower socioeconomic strata, overwhelmingly it is crime turned on the other poor. When crime goes up during periods of frustration and mistreatment of lower socioeconomic classes, it does not take the form of suddenly everybody going into deciding to like scale the wall to the palace there and rip off some of the Ming vases, it is victimizing the people who are victims right next door to you.

Frustration-Balls of Rage Model (52:36)

During times of economic downturns, the rates of crime and poorer neighborhoods go up and it's almost always turned on individuals in that neighborhood. So that supports this picture as well. One interesting thing that argues against frustration displacement models, and this is looking at animals and looking at what happens to levels of aggression during periods of famine. And this has been studied in a surprising number of species, and what you've got are two very opposing predictions. First one is, if what aggression is about is built out of frustration, need, pain, fear, hunger, things of that sort, the prediction would be when you look at populations of animals during periods of famine, aggression should go up over food resources. And this comes with the qualifier that these studies have to be during a period when animals are having to work harder to get the normal amounts of food rather than that they are being calorically deprived because obviously behavior is going to be changed then. So frustration displacement model predicts that during periods of famine, aggression goes up in social species. A very different model would predict exactly the opposite. And what the bulk of the literature has shown is during periods of famine and wild animals and social groups, aggression tends to go down rather than up. So at least in that realm, that tends to be a vote against one particular type of frustration displacement aggression tends to go down. And in fact, a term has been given for that by people who think about these things, it's referred to as behavioral fat. Why does aggression go up, for example, among young male lions, not during the periods of the year when there's not much food, but during the peak of, say, zebra migration, what's going on there, you got a lion, it's sitting there saying, I'm not hungry, my stomach's full, there's nobody to hunt, nobody's going to mate with me right now, so I might as well go get in a fight with somebody. And in that scenario, what aggression is about is use of surplus resources when there is an excess, it is behavioral fat. And in lots of species, you see aggression as a model of behavioral fat rather than purely resource deprivation. One interesting interpretation that I've seen of one type of violence, which is the notion that violence, aggression, competition being built around limited resources, a very interesting interpretation of the fact that there's a lot of people in the world that are in the world. A very interesting interpretation of clan violence, of feuds, of vendettas, of retributive violence, which has been a large percentage of violence over the centuries, a way to formalize that is to think that these are two different clans at war with each other, competing for a very, very singular resource, the one who does the last bit of retribution. That's what they're competing for. So an interesting interpretation there.

Behaviorism (55:54)

Third broad branch of people thinking about theorizing about aggression, and these are, of course, our behaviorists back to Watson and Skinner and give me a child of any background and let me control rewards and positive reinforcements and punishments and negative reinforcements, all of that. And I will be able to regulate any aspect of behavior. We know that whole approach by now. We saw all the ways in which that fails in explaining classical, ethologically based behavior. But in the standard behaviorist view, have enough opportunities for punishment and you can shape, you can condition a way you can eliminate aggressive behavior. And all you need to do is think for two seconds and see that that is very limited in its applicability. Nicely, huge number of experiments have been going on for two centuries in this country, looking at that, which is looking at rates of crime as levels of punishment, the length of jail sentences, the likelihood of being caught, things like that, as the punishment likelihood and severity changes, does that change the likelihood of crime? Most studied is the very specific question of what does the death penalty decrease the amount of murders, as different states have eliminated the death penalty, as they've reinstated it, things of that sort, does changing your behaviorist realm of punishment that you could get for killing someone, does that decrease the incidence of murders? And what you wind up seeing is, in some cases, yes, absolutely. When you are looking at murders that involve premeditated violence, when there's someone who is sitting there for months planning how to do this, when somebody who is hired to kill somebody, things of that sort, when there's planned in advance, increased likelihood of death penalty does indeed decrease the likelihood of premeditated murder. However, it does not touch for a second impulsive murder, crimes of passion, things of that sort, and that makes perfect sense. There is no person who has just been insulted in a bar and pulls out a gun, who stops for a second and thinks, wait a second, did the state legislature pass that new law last week? Let me think about it. They don't think about that because they don't think. The majority of violence in that realm is un-premeditated. Mostly what the studies have shown is changing the severity of punishment for murder does not particularly change the murder rates. So, these broad different sorts of views, aggression as inevitable, biologically inevitable, all environment can do is shape the frequency a bit, aggression as solely a product of fear, frustration, anxiety, resource deprivation, aggression solely as a set of behaviors that could be shaped by reward and punishment to the point of going away. What do you actually see when you see some aspects of environmental impacts on aggression, particularly early in life? What do you wind up seeing in terms of learning to be aggressive? The theme that comes through over and over again, as I've referred to, is the notion that a lot of what early experience is about is not learning how to be aggressive, but learning when to be aggressive, the appropriate context for it. Whoa, my pages disappeared. No wonder it seemed to have just jumped. Okay, let's just do that for a moment here. Oh, that's what we're talking about next. Okay, so let's get rid of that. Okay, so what that ushers us into, I say, trying to make it seem as if that's a seamless transition. What, okay, let's all sing for a couple of minutes here, only with this piece of paper. Okay, so what this now brings up is what does early experience in terms of environment, in terms of upbringing, what does that have to do with the aggressive behavior, empathy, compassion, all the things we are looking at here.

Psychological Aspects Of Morality

Theory of Mind (T.O.M.) (59:57)

Because never more than during development to these themes of is aggression inevitable, is aggression purely about social learning, is aggression purely about displacement. Never more is a clearer in terms of the consequences than during early development. So, what's the transition during development towards the development of aggression, the development of empathy, the development of compassionate behavior, cooperation, all of that, widely, widely studied, tons of research that's been done in this area, much of it ultimately framed along the lines of what is the development of moral standards, moral development in kids. But what's pertinent comes long before that. Very early in life, the most pertinent initial transition is when kids start distinguishing between animate and inanimate objects. And that comes remarkably early during the first few days to weeks of life, that's very early transition. And as I think we have heard already, what you see is the specialized region of the brain, the fusiform cortex that responds to faces and the fact that autistic individuals that part of their brains do not respond to faces as an everybody else, not necessarily were shamed between animate and inanimate. So initial stage first beginning to get that dichotomy down. What then emerges is the first evidence of kids beginning to differentiate themselves from the world around them beginning to get a sense of self. And this is where kids begin to get ego boundaries of some sort. Before that happens, a kid very typically views themselves as basically being continuous with mom. And this is the world where you see a 12 month old where mom has a cut on her finger and has been walking around with a band-aid and the kid is there all day saying that they have an owie on their finger. Because they are mom, mom is them, there is no particular boundary between them around a year of age is when you begin to see this starting to happen. So a sense of self, what that of course has to be a precursor for is a sense of others being selves, theory of mind. So we've already heard the building blocks of theory of mind. When do kids first begin to recognize that not only are they a distinct individual, but there are other individuals who are not interested in their own mind. There are other individuals with different information, with different thoughts, ultimately with different feelings. And when does that begin to emerge typically between ages three to five. And we've already heard some of the basic sort of tests that are done to reveal that. And what you also see is it is very, very emotionally contingent. Take a kid who is doing great theory of mind when you read them some abstract story about Sally Mae or who is it? Sarah Anne. Sally Anne? Okay, I seem to not be able to get this one down. That kid with a doll there read them and they may be at a point where they're three, six months into being able to perfectly do tests like that. But get them in an emotionally aroused circumstance where it's something they really care about as opposed to like some story there and the theory of mind goes down the tubes at that point. It is not an all or none transition. It is one that is vulnerable potentially to strong emotions go figure not surprising. So what a lot of people have thought about is is theory of mind a prerequisite for empathy. Is it possible to feel somebody else's pain and act upon it without having a sense that there is somebody else who has different thoughts and most importantly different feelings and they can be bad feelings. Things that sort is theory of mind a prerequisite for empathy and the general sense among a lot of people in the field is yes indeed. It is necessary but not sufficient.

Level 1 Empathy (01:04:00)

And where you see the most dramatic dissociation between theory of mind and empathy is when you look at sociopaths. Every sort of test that could be done sociopaths have spectacular theories of mind. They are incredibly good at manipulating people and manipulation requires a very very astute theory of mind to be able to do that. Sociopaths have the prerequisite of theory of mind that most people think that empathy requires but what you have there is it stops at that point. It does not continue. It is a means for exploitation rather than the transition into true empathy. As we've already heard there is evidence for empathy like of that sort and theory of mind and apes so we're not the only ones. So general view being that you don't get empathy until you get theory of mind. But there's always been this confusing sort of counter bit of evidence where you see stuff like the world of a 15 month old where somebody is sitting in the room crying. And often in experiments someone who is pretending to and the 15 month old will come up and try to give the passe to the person and try to put it in their mouth. Here feel better. So possible interpretations number one being that this is already evidence of empathy. Empathy not yet having the theory of mind element of not only recognizing there's somebody else but not everybody likes passe's especially mind that I've been slobbering on. Other interpretation and irritation decreasing strategy which is it's simply distressing having the person in there acting all upset and what's going to make them shut up. I know I'm going to go over to them and give them my stuffy and maybe that will work. It is not empathy. It is irrit attempts to get away from this irritating context. Studies very interestingly though arguing against that. Take kids during their first three to six months of life and show them a scenario where two people are interacting. One of them needs help and the other helps them or one of them needs help and the other doesn't. Or one of them has something and the other one takes the thing away from them so either pro social behavior neutral or anti social behavior and kids in that age range already prefer to look at the individual who's doing the pro social helpful thing.

Kholberg Moral Development (01:06:25)

Some sort of elements of this are already in there before formal theory of mind nonetheless that seems to be a big important part of it. Next so you got yourself theory of mind and the next step in there is not only recognition that somebody else has other thoughts but they have other feelings. They can be very different from yours. They can be legitimate and what we begin to enter now is the more formal world of moral development in kids. The name V without question most influential psychologist in this whole field. One of the biggest names in the whole field in the last century this guy Lawrence Kohlberg and Kohlberg's famed stages of moral development in kids. Okay how many of you are familiar with Kohlberg? Okay how many are not? Okay good Kohlberg it is. Okay so Kohlberg Lawrence Kohlberg was psychologist at Harvard super influential and he came out of tradition established by the Swiss psychologist. It's never possible to just say the psychologist you always have to say the Swiss psychologist Jean Piaget and Piaget brought in the whole notion of sequences of development. Sequences as in kids crawl before they walk. Kids comprehend language before they begin to produce it and Piaget generated a whole world of information about stages of cognitive development at what age do kids have object permanence. You cover something is the object still existing or do you get all surprised when you take the lid off and it's still there and start breathing faster stages of cognitive maturation. And Kohlberg came out of that tradition looking instead at sequential development of moral development.

Ego Self Other-Oriented Motivation (01:08:13)

A theme that ran through this whole sort of world of sequential whatever is is that you don't have the sequence change. There are no kids ever who run before they're crawling. There are no kids who are fluidly producing language before they comprehend it. It's a set sequence. What does experience do it regulates the rate the speed with which you make the transitions. So Kohlberg introduced the whole notion that there are also sequences of moral development. Very broadly what he came up with were six different categories, six different steps. And people I take it have been spending the rest of time deciding whether there is in fact 60 sub parts of that and splitting and lumping all of that. Broadly the six stages fall into three categories. What he called pre-conventional moral reasoning. Conventional moral reasoning and post-conventional moral reasoning. Okay, you might have guessed that after the pre-unconventional. But those were the three phases and broadly they could be termed or framed in terms of what the motivation is for acting morally. In the pre-conventional stage why do you act morally because you may get caught? Because you may get punished. Because if you act morally maybe you'll get a reward. What's in it for me? A very ego-centered set of motivations for moral behavior. Then transitioning into the conventional stage how that is typically framed as is your motivations for your moral behavior are based on shared group values. Shared group conventions. Things built around social norms. Rules. Laws. Even a higher level belief in the importance of law and order in a society transcending any given law. And notion that if you follow conventional rules of moral reasoning you will be viewed by society at large as a good girl.

Morality and Kids (01:10:15)

As a good boy at whatever developmental stage your moral reasoning being built around society-wide rules and implications. Finally the post-conventional stage is built around transcending that. The word transcendence plays a lot in that realm of Colberg's thinking. The notion that there are all sorts of examples of moral reasoning, moral decision making where you are in fact violating the rules of society. You are breaking a law. You are breaking a social norm. What's the motivation there? The notion that there are things that are more important than the laws of society. There are things that are more important than what everybody else thinks. What this has become is the world of civil disobedience. This is the world of saying bad laws need to be broken. This is the world of people saying I don't care if I get punished. I don't care what everybody else is doing. This is the right thing to do. That would be a post-conventional Colberg stage. The main thinking that goes into sort of Colberg then looking at adult moral reasoning is as you go through these various steps and these sub steps and all sorts of tests that ostensibly sort of tapped into it. Not everybody reaches the same Colberg stage in adulthood. People will stop in their conventional stage. Some people will get to a partial post-conventional stage. The way of thinking of people within this framework is how far do you progress in your Colberg in sort of ladder of complexity sophistication in your moral reasoning. Ways in which this would look. Take somebody and you can have a Colberg stage of being very focused on the individual sort of studies that will be done. You have a kid who believes there is a baseball team and they're told that here's a bunch of kids. There's one more spot left on the baseball team and this has always been a team for boys. And boys play baseball better than girls. This was the sort of way this type of study was done some decades ago. And here's a girl. Typically we don't allow girls on the team but this one girl wants to play. And what you see is at a pre-conventional stage what kids are most likely to do is reason morally on the level of individual consequences. Saying things like, "Well, she hasn't gotten to play before. All of these boys have gotten to play before. She's never gotten to play before. It would be fair. She's the one who should get to play." By the time you get to kids reaching conventional moral reasoning stages what they're doing instead is saying, "Well, boys are better. We need to put one of the boys on because the team will be more successful." Suddenly moving from the level of individual consequences to norms and law and order and things of that sort. So general framework of Colberg and amid that becoming the dominating model there has been a gazillion totally appropriate criticisms of it. One is focusing right off the bat on gender and the fact that Colberg doing his stuff mostly in the 1960s had the same bias. This is most everyone at the time which was a very disproportionate share of the studies were done on males rather than females. The notion that Colberg in reasoning sequences of moral development are a better fit for what happens in boys and men than in women girls. That boys are more about justice. Girls are more about affiliation, reconciliation, things of that sort. So a gender critique. Next is a cultural critique and there's been a whole world of people doing cross-cultural moral development and kids-type studies.

Colberg Moral Reasoning Model (01:14:03)

And one thing that you see is that the stages don't necessarily move in this inevitable sequence in different cultures. So that has been sort of a blow to this. This is how all humans are. What you also begin to see is when you begin to couple sort of other values with your moral stage. For example, what studies show is people who are trained in childhood to respect ability more than effort are far more likely to endorse social norm moral reasoning over social justice reasoning. That is shown. What's that one about? Again, ability having something that you view as transcendent as not intrinsic to sort of the effort of the person. Okay, that's making no sense. I just tied that into not don't listen to what I just said.

Dominance And Its Influences

Ability vs. (01:14:58)

Nonetheless, here's what they have found. People who are brought up to value ability more than effort tend to value moral reasoning for social norms. Rather than for social justice. They are less likely to get to a post-conventional, cold-berg stage. So that being one of the backbones of people who think about this, but a whole world of additional things in moral development and kids. How do kids first learn that sometimes it's okay to lie? How do kids learn that in fact you're supposed to tell grandma that you love the sweater even though you think it's awful? Or do not tell her you already have this toy. How do kids learn to lie? Related to that, how do kids first learn the difference between rules and principles? Rules that are meant to be less breakable, principles where you are having to balance them to weigh them. When do kids first learn about the possibility of there being bad laws? Because something is a law doesn't mean it is necessarily good. When do kids first start to consistently make distinctions between, or see the similarities between intended harm and successful harm? At an earlier stage, kids discount activities that don't actually produce the harm that it was meant to. So if it's not successful, when do kids begin to see that they are more similar than they initially respond to all of these nuances, subtleties here? Okay, other ways that people have thought about development of aggression. Now comes the issue of peer groups and community and aspects of what sort of world are you being exposed to. What this always comes down to is what are the effects on violence in growing up in a violent setting? In being witness to violence and being a victim of violence, we've already seen one realm of this, which is the greater the incidence of childhood abuse, the greater the likelihood of adult antisocial behavior, and a huge interaction with genes that have a relevance to the neurochemistry. What else is shown? Consistently study after study shows that independent of family circumstances, socioeconomic status, personal experience of violence after controlling for all of that, growing up in a neighborhood where there is a lot of violence feeds into a higher rate of violence in adulthood. What it does is rationalize it. What it does is desensitize it. So that is shown consistently. What is shown is there is even a stronger effect tapping right into this when one is witness to violence within the family. So violence within neighborhoods, this was worked on a number of years ago, sociologist psychiatrist at Harvard named Felton Earls, going through very, very careful studies controlling for all sorts of factors of how many violent acts were kids seeing in various communities as they grew up, and that is a very strong predictor in and of itself. Violent acts within the family, even more so. That, of course, brings up another one of the great perpetual questions is what is the effect on adult violence of having been a kid growing up watching a lot of violent television, or a lot of violent movies, or as the studies are now beginning to be there to ask violent video games, what's that one about?

Modifiable or Not (01:18:18)

And every parent for decades is known, of course, what the worry is, which is watching violence in any sort of version of media like this, is going to foster violence intensely well studied subject, and what the results generally show is, yes, here it comes again. The same exact thing. Watching a lot of violent television when you were a kid makes you more violent if you already are tending towards being violent. What it does is it exaggerates the pre-existing social tendencies. You know that drill by now, after this lecture, you can now pull out half a dozen examples of X does not cause whatever, but it magnifies or blunts pre-existing tendencies. That's what the literature consistently shows. Violent television, movies, reading material, and violent video games does not increase the likelihood of being violent. It's only in kids who were already predisposed towards that. Next, more aspects of environment. Here we have the summary, a classic study that was done a couple of decades ago, a couple at the University of Toronto named Alien Wilson, and what they did was look at the likelihood of men committing murder as a function of their age. And they were interested in age because they were viewing that as a proxy for testosterone levels. And what they showed, looking in three different cities, Chicago, Toronto, and London, which was in all those cities, you were likely hood of being violent, of being committing a murder. If your male was somewhere late teenage years into early 20s or so, I drew this a little bit wrong. And that was fascinating to them because that happens to be the time of life when males have their highest testosterone levels. And what was hugely interesting in that study was that the curves were super-imposable in these three different cities. One American city, one Canadian city, one British city.

Testosterone most important (01:20:22)

So, you can now ask the sort of question that we've had coming up since the behavior genetics lectures, which is, if you could know only one thing about these group of individual men, and you want to know something about predictability of their being aggressive, what's the one thing you would want to know? Well, it would be mighty useful to know how old they are. Because this suggests a big age effect, and maybe that's got something to do with a high testosterone at that point. And one of the sort of relevant to that, sort of a classic sort of soundbite in criminology, is one of the leading causes of decrease in criminal behavior is people turning age 25. It's a very, very strong maturation curve. Okay, so look at that. Look at how this is important. This is sort of life history trajectory. But then you look at something even more interesting, which is you ask, so how many murders are there in each of these cities? And in their database, the London one averaged 30 a year, Toronto averaged 50, and Chicago averaged 600. So, now you have a choice. You could find out one fact and one fact only. Do I want to know how old this individual is, or let's even be fancier, do I want to know this individual's testosterone levels and his age, do I want to know that information, or do I want to know what society he's been growing up with, without question, you get more predictability.

Heritability Genetics (01:21:35)

This is far more important. We now can sort of put in heritability type interpretations. Yeah, this is important, but it doesn't hold a candle to whatever these environmental factors are in there. Far, far bigger effects than the age effect happening here. What else? Okay, so again, this business about socialization involving lots of teaching of context. And more evidence for this came from one of the all time classic studies, one that was referred to in the sex lectures, and this was the work by that guy, Harry Harlow, raising captive recess monkeys, and we heard different variations, raising them without a mother, raising them in social groups with peers, raising them in complete social isolation. And what we heard last week was, it did not change the fixed action patterns of sexual behavior, it changed the context. In other words, you had monkeys who had grown up in some of the most of the isolated environments, and they were trying to do sex normally, but just the things that monkeys don't normally have sex with. The same exact thing in the realm of aggression here, being raised, for example, in social isolation as a recess monkey, then in the young adulthood, you're putting into a social group and you have perfectly normal threat yawns, you have perfectly normal fixed action patterns of dominance and subordination. What you don't know is who you should be doing it to. And Harlow showed that these animals then put into social groups were threatening high ranking males, they shouldn't have been going anywhere near, were terrified and subordinating themselves to little pipsqueak infants, they're things of that sort, they had not learned the appropriate social context.

Low ranking infant (01:23:32)

And that's an awful lot of what's going on. Example of this, and this is one that I actually observed at my baboon some years ago, and this business about context. Back to baboons and female baboons, the business there, if you are high ranking female, you have far more options to be aggressive than if you were a low ranking one. You inherit your rank from your mother. If your mother is number one on the troop, you, her first daughter, will be number two. If your mother was number twelve and you're her second daughter, you're her first daughter. If your second daughter, you're going to be number fourteen, it's a hereditary system. And this was some years ago where it just happened, and one of my troops, the highest ranking female who was still fertile, her mother, matriarch, who's one step above her, but this female, the highest ranking fertile female, gave birth, had her first daughter. And it just happened a day later, one of the lower ranking females in the troop, also gave birth and had a daughter. So suddenly you've got this great side by side comparison. And what you see was every developmental landmark, the high ranking kid was hitting earlier than the other kid, just in terms of sheer physical matoration, coordination, all of that. When they were about a week old, they had their first social interaction. Low ranking infant spots the high ranking one, and obviously is thrilled, finally seeing somebody else the same size as them instead of just looking at everybody's knees. And the low ranking one goes wobbling over to sort of greet this other one. And as she gets about three steps away from the high ranking infant, low ranking mom leans over, grabs her daughter by the tail and pulls her back. And she had just gotten her first lesson in her appropriate social rank and her appropriate social behavior. She had just gotten the first lesson that that is not somebody you go up to and interact with. If you're going to interact with her, what it's going to consist of is you sitting real still and don't make any eye contact and hope she doesn't notice you. And if she does immediately make a subordinate gesture, you do not go and walk up to her to greet her. And the amazing thing is at that point, you pick up and you come back 25 years later and they're going to be two old ladies out in the savannah there doing the same exact dominance interactions that they learned in their first week of life. Very, very early social training for this. Finally, another bit of evidence for that social training, which we already heard about, the captive hyenas growing up without adults there took a much longer to come through with the same social dominance system that you would see with animals in the wild.

Social influence on dominance (01:26:04)

So the question then becomes, amid all of this social environment mattering hugely, how important are parents and how important is peer group. And a very, very interesting book came out about a decade ago by a psychologist named Judith Rich Harris called the nurture assumption. And what she did was basically strongly attacked the literature on parental influence on child development. And her argument was that peer influences are vastly more powerful than the field you usually recognizes. Great story with her. She was about 60 at the time. And many decades before she had been a graduate student in psychology at Harvard and something was not working out and she was expelled from the program and the chair of the department, a guy named George Miller at the time, was the one who told her that this wasn't working out. So good luck and off you go to sort of trade school. And she proceeded to never finishing her degree, become a science writer and writing science books for kids or whatever. And around age 55, she started writing this book, which wound up being an amazing book, extremely influential in the field, where she got all sorts of prizes for being the first book by a young author, young author, 60 years old at that point. And one of the great ironies was she got like the grand prize for a first book at the annual meeting of the American Psychological Association, getting this prize called the George Miller Award, given out by the now very elderly George Miller. So one of those like nice ironic ending things and she didn't like trip them up or something like that as she perhaps might have considered. Okay, so Judith Racharis. So her basic argument is that peer socialization is really, really one of the most powerful things. And where she begins her argument is one which as soon as you think about it is really striking. You look at children who are growing up in a household where the home language is a different one than the dominant language in the culture. You're growing up in an immigrant family. And what the studies show is by age four or five, you were developing the accent of the community around you, of your peer groups. By age four or five, you were already beginning to become embarrassed by your parents accent. By age four or five, you are beginning to answer their questions or their conversation in the home language and answering it in the outside language. This occurs at an amazingly early age. And as soon as you think about it, oh, of course, somebody whose parents are from Maine, but they grew up down in Louisiana, they're not going to grow up with a main accent. They may be able to mimic their parents very readily, but they're going to develop a regional accent. People pick up the accents of their peer group, not of their parents. So she uses that sort of as the jumping off point for beginning to argue all the different ways in which peer groups are the things that matter.

Conformity And Moral Acts

Conformity and conventionalized behavior (01:29:11)

And at the end of the day, what parents are mostly good for is determining what peer groups kids have access to. Sort of evidence she would show. And this begins the whole world of conformity and conventionalized behavior by groups. This begins a whole world of the studies where showing you arbitrarily break kids into groups by age group, and they start having disparaging beliefs about the other group. This is suddenly zimbardo studies. This is suddenly put people arbitrarily into one category or role, and they begin to over-identify with that group. Here is one of the greatest bits of evidence for peer socialization I've ever heard, and this was documented in at least two different people's memoirs, people who were actors on the set of the original planet of the Apes movies in the 1960s.

Unicef champion campaign #forachild (01:30:03)

And what they noted, I think you could either there, besides being one of the three or four humans, you could either be a chimp or gorilla or an orangutan, all of which were not anatomically correct or politically correct. But what they wound up seeing there was two of these people in their memoirs noted that by the first week of filming, having happened, people sat at lunch separated by species. All of the actors who were chimps ate together. All of the ones. And these were people who had friends. Some of their best friends were orangutans and things of that sort, who they had known for years. But two different people's memoirs noting, sort of who were actors in that noting this bizarre thing that emerged that people would only have lunch with their other primate species. So that presumably vindicates everything that Judith Rittara says. So what she has done is reinterpret certain findings. For example, showing that one of the things that you find is kids growing up, boys growing up in households without a father have a higher chance of antisocial violence as an adult. And what she does is take apart that literature and shows that what the actual variable is, is that boys growing up in families without a father, single parent household, single mother, they are more likely to live in a poorer neighborhood.

The Interview Gradient Hypothesis (01:31:23)

And it is in fact the peer socialization there, which is the driving force on it, fancy statistics to show that that's the sort of argument she makes. Finally, one of the most interesting studies that's ever occurred in this realm came out about 15 years ago. One law professor here at Stanford and one economist at University of Chicago making a very interesting argument as a predictor of criminal behavior in people. And what these two did, Levitt and Donahue, they dealt with what was then emerging as a really interesting sociological phenomenon, which was that somewhere since the late 1980s, the crime rate in this country has been plummeting. Every city, every state, it's been going way down. And for years, people have been wrestling with what's going on with the decreased crime rate in general. If you have a more conservative bent, what you would emphasize is building more prisons during this period, three strike laws, things like that that have put in more institutional punishment, more policing. If you have a more liberal bent, what you emphasize is how good the economy was during the 90s. But that winds up being problematic because the crime rate has continued to drop over the last three, four years, amid the economy tanking. All these various explanations explain a bit of it, but what these guys argued was as follows, that the decreased crime rate that started in the United States in the late 1980s was due to Roe v. Wade. Here's what they would show. They would show that as each state would legalize abortion, you would have about a 12 to 15 year lag time before you would start to have the crime rate drop. The crime rate during the first five years of the crime rate dropping would entirely be due to fewer teenagers entering the criminal justice system. By the time it was a decade and a half or so passed Roe v. past that first point, the dropping crime rate was entirely due to fewer 15 to 30 year old. And it just marched out from their state by state. What their numbers showed when they did what were apparently some pretty fancy convincing statistics was that Roe v. Wade accounted for about 50% of the drop in crime. What's that telling you? One of the most depressing things I can imagine, which is a huge, huge predictor of growing up to be a violent, anti-social individual, is having been born when nobody wanted you to be born. And what Roe v. Wade, what the ability to have abortions introduced in much of the country at that time, introduced was the ability of someone to not have a child who they didn't want to have. Being born to a mother who doesn't want to have you, that turns out to be a pretty big predictor of life not going well after that.

Coalberg stage (01:34:13)

Final piece, final piece in this, which is now when you look at all of this development and aggression and moral, whatever, what does it wind up looking like in adulthood? What this translates into is asking the question, how much does one stage of coal, Berge, and moral development actually predict who does something moral? In other words, is there a good correlation between moral reasoning and moral behavior? And what the literature is absolutely clear on is there's not a particularly good connection. You've got some fancy, dancey, post-conventional transcendent coal Bergean stage, and you even have a certificate to prove it, and that's not remotely a predictor of you being more likely to be the person who steps out of the anonymous crowd and saves the drowning child. There's no connection with coalberg stage. Having the fancier coalberg stage is a pretty good predictor that you'll be a moral philosophy professor at an Ivy League college instead of a state school. If you're stuck in an earlier coalbergian stage, it's a very abstract academic measure.

Who is most likely to do the Truly Brave Moral Acts? (01:35:21)

It is not a predictor at all over who will do the truly brave, unexpected moral acts. So what's that about? That taps into something that I think we've already alluded to in here, which is certain ways in which information is stored, certain places in the brain that information is stored, as follows. So there's this dichotomy in sort of the neurobiology of learning between what is viewed as explicit learning and implicit. Explicit declarative learning, implicit procedural learning. Explicit declarative learning is you learn a fact, you know a fact, you know that you know the fact, you can consciously make use of the fact and strategize and use it in an executive way. Implicit procedural memory instead is stuff that, as always termed, your hands know better than your head does. How to do stuff with your hands. The other day, sort of showing that in terms of damage to the amygdala and the frontal cortex and people without timer's disease, explicit declarative memory goes down the tubes, but this is the person who can still knit. This is the person who could still drive a car, things of that sort. Procedural implicit memory is not stored in the hippocampus and cortex, and is predominantly a phenomenon of the cerebellum.

Jack Key Thinking and Carnegie Foundation (01:36:46)

So you look at the people who do the profoundly brave stepping out of the crowd step. Steps there, the ones who regardless of what their cold burgy and stage might be on their essays that they write for college finals, when you look at the people who actually do something, what you see are two factors that consistently come up. And this has mostly been studied by the Carnegie Foundation that every year gives out awards for the most heroic acts of the years, and they've actually studied who these people are, what the differences are. The first one is that you have grown up with a very strong, consistent, frequently stated imperative to act morally and to act bravely and to not care what other people think. That's the first thing that you see. And the second thing that always pops up is one that is the complete neurobiological outcome of that, which is when they then interview these people and say, you leapt out of this crowd and ran into this burning building and almost got yourself killed to save this child who you didn't even know. What were you thinking when you did it? And people's answers is always the same. I wasn't thinking. I didn't think before I knew it, I had run in there. Before I knew it, I had leapt into the river. What are we looking at here? We are looking at a moral act, not as the outcome of your frontal cortex, wrestling you into being brave and moral and all of that.

Role Of Brain In Morality

Frontal Lobes Tell us To Be Good. (01:38:16)

You were looking at an implicit pathway. You were looking at, I didn't think. Before I knew it, I had leapt in the river. You were looking at what happens when something is over learned during childhood. It is not something that you have to sit and consciously wrestle with. Fascinating paper a few months ago from that same Josh Green who did that trolley car study. What he did was people were playing some sort of game where they had to predict an outcome and they would get rewarded if they predicted right and they set it up in some totally clever duplicitous way so that there would be periods in the game where the person had the option to cheat. They were able to tell by the rate at which they were suddenly getting better answers if during these periods suddenly they were being statistically significantly more successful they were cheating.

Morality Education

On the Teachability of Morality (01:39:06)

They had them in a brain scanner and were able to see what was going on. You look at people who would cheat and what happens when the signal comes on indicating that it is one of these sessions where they could get away with cheating, their frontal cortex is lit up like crazy. What were they doing? They were wrestling with Satan. They were asking those neurons to do something or other down the amygdala before they did the wrong thing and the degree of frontal activation was not particularly predictive of who actually did cheat. You fell into the cheater category if they could show that you ever cheated during one of these and thus looking at you the rest of the time when you had the opportunity and didn't. It wasn't particularly good predictor of whether you cheated or not but it was a great predictor of people who were willing to even cheat once. Now look at the people who never ever cheated and of course one prediction would be that they have frontal neurons poking out of their head. They are so big and energized and the frontal cortex didn't move an inch. When the possibility of cheating came up there wasn't the remotest change in frontal activation. This was not them wrestling Satan to the ground. It wasn't there. There was no temptation. It was an implicit pathway. It was not sitting there saying, "Ooh, what if everyone did this?" "Ooh, it's important that we have laws and what if I get punished or it?" It is simply before I knew it I had jumped in. I didn't even think about it. What I think this suggests is an awful lot of what moral development is about and the formal stage world is what kind of frontal cortex you're going to wind up with reasoning with your amygdala when you look at the dissociation between moral reasoning and moral behavior and the ones who do the truly brave things. It's got nothing to do with the frontal cortex. It's implicit by that. Okay, so we will pick up on what day is it? For more, please visit us at stanford.edu.

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