[MUSIC PLAYING] Stanford University. [MUSIC PLAYING] So back a little bit. Still back in the neurobiology. Back to the anterior cingulate. Remember anterior
cingulate again. All that empathy stuff,
feeling somebody else's pain. That business about
something metaphorical, something symbolic
about pain and empathy is happening in there. Something people
have been speculating about for about 10
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 are 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 getting
some place or other in there. Totally cool idea. Still not yet demonstrated. 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
Haidt, that guy the other day, arguing that moral reasoning
is mostly after the fact. It's rationalization
for moral affect. Mostly what we're having is
an 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? Is incest OK 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. So really important
feature of his work. 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 in
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, not looking at something that
you can't do in a human-- whatever. You can't look at serotonin
levels and 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. MOA, monoamine oxidase,
this one broken down into a waste product called
5-hydroxyindoleacetic 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 blood stream, in the cerebral spinal fluid,
in the urine, places like that. And the literature is
showing that lower levels of serotonin breakdown
products are correlated in humans with higher levels
of aggression and antisocial behavior. 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 have
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, drive down serotonin levels in the
frontal cortical region and you get more
aggressive behavior. You get more impulsivity. So evidence for that there
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
in the way serotonin interacts with the receptors
in the frontal cortex, your buzzing serotonin pathways. In 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 in 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, violent sociopaths having lower
than normal metabolic rates in the frontal cortex. Some of these pieces
beginning 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. 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 in the stuff. OK. So how do you interpret that if? You believe that low
levels of serotonin give rise to aggression. So what's your interpretation? 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 product, 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
is a mutation in one of these enzymes that's supposed
to break down serotonin. And because of the
mutation, it 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 at this step. So there could be low
levels because there is 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. In 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. How about the genetics, though? What you see are differences
in variance of the gene. That's the critical one
for making serotonin. Basically concept, if
you're not a bio chem type, if there is 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 rate limiting step in the pathway. The rate limiting enzyme, this
enzyme tryptophan hydroxylase, is the rate limiting step in
the synthesis of serotonin. And by now, there is a
literature showing variance on tryptophan
hydroxylase in people. Variance in non-human
primates that begin to correlate a bit
with how much of this, how much of aggression. Not big effects. Back to our 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, scale graph
by now where exactly where this one is heading-- if
I can get the right ink-- which is-- OK. So variants on this MAO
gene, this monoamine 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. And 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
antisocial 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, figurative,
superimposable with this. It's the exact same punchline. Having the bad version
of monoamine oxidase gene does not increase your risk of
antisocial violent behavior. Having the bad
version of the gene and getting brought up in an
environment with abuse 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
antisocial 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 piece of neurochemistry
that's relevany-- and this is not a
neurotransmitter, but this is a nuerochemical
that occasionally gets put into the nervous
system, which is alcohol. Alcohol. What doe alcohol do
first to neurons on sort of the nuts and bolts level? Is alcohol a mimicker of any
particular neurotransmitter? 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 built 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 preexisting
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 rhesus monkeys start attacking
number two and number one. It makes them absolutely
torture numbers four and five. Testosterone does not
create aggression. It amplifies preexisting social
patterns [INAUDIBLE] that's our remove the testosterone
and aggression doesn't go down to 0%. Interaction with social
history, same exact theme again. Alcohol does not
cause aggression. It amplifies
aggressiveness in people who already are aggressive. Along with that, sort of
as a confounding factor, we have this problem that
everybody knows that alcohol makes you more aggressive. And what has also
been shown in studies is that if you tell
people that you have just raised their blood
alcohol levels infusing in either 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 preexisting social tendencies
towards aggression. Modifier over and over
again this sort of theme. And this has been studied
in all sorts of contexts. One really interesting
domain have been people who--
anthropologists who basically study how
people in different cultures learn to get drunk. 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. And 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. So the question becomes,
what are people's behaviors like in these cultures
as they are first having a culture of
people drinking to excess? And the answer is, it depends. It depends on the people who
are teaching you to drink. And what you see
is an interaction between the type
of colonial power that controlled the island at
the time and 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 like French
Tahiti, people get drunk and they all sleep
with each other. Aha. [LAUGHTER] It's a cultural context
specific sort of thing. This shown over and over again. 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 that time point, the
acute environmental releasers. 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 the same language across different species Just as
with sexual behavior releasing 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. 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 the deal of swabbing
the arm pits 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's as dramatic as in other species. So what sort of multi-sensory,
multi-modal 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
10 times, it gets its food. 10 times, get its food. 10 times, it doesn't
get its food. 10 times, you're not
giving it its food. Get the rat good and frustrated. And with great
reliability if there is 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 were a rat or a primate and you were 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. 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 that
after hearing all that heartwarming alternative
strategy stuff of male baboons forming
friendships with females. Meanwhile, the alternative
strategy with a 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 sort of definition 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 breed 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. 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
releasers 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 an 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 are 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 then. And we readily can fit
that into scenarios of frustration, displacement,
and that kind of thing. 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 a fetus, but
in the last minute, in the last hour, the
last couple of days. Where we started, of
course, was 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 0. 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 take someone who instead of
having 200% the normal levels, twice the normal levels, they
have tenfold higher levels, higher than the body
ever normally sees because they are abusing
anabolic steroids and their levels of
aggression do indeed go up. But within the normal
range, you gotta 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. 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
preexisting tendencies. Testosterone is
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 in amazing
example of hyenas and 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. [LAUGHTER] 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 sex 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 is 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, endocrine modulators. They eventually got to a classic
female dominated social system. It took them a
lot longer though. Next hormone, hormones to look
at, estrogen, progesterone. 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 in females. Oh, yes. That again. Same exact thing as
from the sex lecture, substituted from there. Females generates certain
levels of testosterone of related androgens
from the adrenal gland, adrenal androgens, maybe 5%
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 0 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 androgrens. 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 perimenstrual period. The whole notion of
perimenstrual 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 in culture
after culture blah, blah. Cross-cultural argument. Then there's a personality
argument that a lot of people do. Looking at the literature,
the relationship between increased aggressiveness around
the perimenstrual period. Again, notice I'm not
saying pre-menstrual. What the literature
shows is a couple of days after just as much
as a couple of days before. So perimenstrual. 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 sound bytes. That aggression goes up and
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 I be off having babies like female hyenas? And, oh, that's what it's about. It's the deep psychoanalytic
conflict and evidence that yet again you have
passed up the chance to be a mother and
reproductive so you're going to be in a pissy mood. [LAUGHTER] 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 for that? 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. That's the perimenstrual
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
pyschodynamic, and none of the 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 is 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 perimenstrual shifts
in behavior in cultures that are more free about bodies
and more sexually uninhibited. And presumably this
tells you that something about baboons'
sexual inhibitions, there's not a whole
lot of evidence for that perimenstrual
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. None the less, 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
subject's permission. But this was a study
done some decades ago. Women become more irritable. 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. [LAUGHTER] Irritability among men who
have significant others, women, peaks around the time that
she as menstru-- whoa, we've got either some sort of
viral, infectious, intersexual 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 week day, 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 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, OK,
perimenstrual 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? Quick memory from
a few weeks ago. What's one of the unlikely
things that progesterone does? [INAUDIBLE] 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 endorphin, a neurotransmitter slash
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 endorphin
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, norepinephrine, 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. Oh, does that teach us
something about aggression? Not in the slightest. What you have instead
is the nonspecificity. Levels of glucocorticoids
will go up roughly equally whether you were running for
your life or running in rage or running in joy. That whole deal again,
sympathetic arousal. It's nonspecific. And back to that sound
byte from two days ago, the opposite of
love is not hate. The opposite of love
is indifference. And endocrinologically,
this is the case again. 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
as 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 in so far
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. 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 pellet after pressing the lever 20 times and I didn't
get the lever, I'm frustrated. Not a minute's worth of
environmental releasers. But instead general
pictures of what environment has to do with aggression. Some of the broad theories that
have come out over the years. Let's take a five minute
break before that. To quickly go through
this deal again. So you've 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
tone 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 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 degradative 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. [LAUGHTER] Very, very frequently seen. And hopefully some of you
have taken part in experiments like that yourselves
over the years or may foist that one
off on someone else. So now pushing over toward
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 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 was the main
advocate of that? Our ever reliable friend
Herr Nazi Konrad Lorenz. Konrad Lorenz, after he had
gotten out of his prison camp after World War II for
being a Nazi propagandist and he sort of dusted himself
off and got his ethology empire going again
and remarkably was forgiven by the other
elder fathers of ethology, including Niko Tinbergen,
who spent much of World War II in a concentration
camp and he is the one who led
the move to make sure that Konrad Lorenz was
welcomed back in the community even though he was an
unrepentant Nazi swine. But-- so after Konrad
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 the 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. [LAUGHTER] But what you see is a whole
book, 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 pattern of aggression. Intrinsic in his model
also and explicitly stated was eventually his toilet bowl
fills up with enough-- actually it's not the toilet
bowl, it's 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 releaser 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've 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
Lorentzian model, which was enormously,
enormously influential and everybody learned
about this in Intro Anthro through the 1960s. '60s
And it would take you about two seconds
to shred this one. How many of you have
ever murdered anyone? You never know. People are kind of drowsy,
checking their emails and suddenly confess. How many of you plan
to murder somebody? Yes, we are like the most
dangerous aggressively 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 as
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 legitimatizes 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 amygdaloid 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
in 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 troop, for example,
almost 50% of aggression is displacement aggression
after somebody loses a fight or loses access to a 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 and 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. During times of
economic downturns, the rates of crime in
poorer neighborhoods go up and it's almost always
turned on individuals in the 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 in
wild animals in 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. It tends to go down. And in fact, the 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 is not much food but during the peak
of, say, zebra migration? What's going on there? You've got a lion. It's sitting there
saying, I'm not hungry. My stomach is 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 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. Third broad branch
of people thinking about theorizing about
aggression-- and these are, of course, our behaviorists. Back to the Watson and
Skinner and give me a child of any
background and let me control rewards and positive
reinforcement and punishments and negative
reinforcement, 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 away, 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, 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 it is 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 it is planned in advance,
increased the 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. And the majority of violence in
that realm is unpremeditated. 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 page has disappeared. No wonder it seemed
to have just jumped. Let's just do that
for a moment here. Oh, that's what we're
talking about next. So let's get rid of that. So what that ushers
us into, I say, trying to make it seem as if
that's a seamless transition-- what, OK. Let's all sing for
a couple of minutes here while I look at
this piece of paper. [LAUGHTER] 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 aggressive
behavior, empathy, compassion, all the things we
are looking at here? Because never more
than during development do these themes of is
aggression inevitable, is aggression purely
about social learning, is aggression purely
about displacement-- never more is it 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 a very early transition. And as I think we have
heard already, what you see is this 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 in everybody else, not necessarily distinguishing
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 it 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
with different information, with different
thoughts, ultimately with different feelings? And when does that
begin to emerge? Typically between
age of 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 Ann? Sally. Sally Ann? OK, I seem to not be able
to get this one down. That kid with the doll there. Read them and they
may be at a point where they are three, six months
into being able to perfectly do tests like that. But get them in an emotional
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 a
somebody else who has different thoughts
and, most importantly, different feelings? And they can be bad feelings,
things of 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. 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 in 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
paci 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
pacies, especially mine that I've been slobbering on. Other interpretation, an
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 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. So some sort of elements of
this are already in there before formal theory of mind. None the less, 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. And the name, the-- without
question-- the 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. How many of you are
familiar with Kohlberg? How many are not? Good. Kohlberg is. So Kohlberg. Lawrence Kohlberg was a
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 see 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. The theme that ran through
this whole sort of world of sequential
whatevers 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 these six stages
fall into three categories, what he called preconventional
moral reasoning, conventional moral reasoning,
and post-conventional moral reasoning. You might have guessed that
after the pre in conventional, 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 preconventional 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 of belief in the importance
of law and order in a society transcending
any given law, a notion that if you
follow conventional rules of moral reasoning you will
be viewed by society at large as a good girl, 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
Kohlberg'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 because it 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 Kohlberg stage. The main thinking that
goes into sort of Kohlberg then looking at
adult moral reasoning is as you go through the various
steps and these sub steps and all sorts of tests that
ostensibly sort of tapped into it, not everybody
reaches the same Kohlberg 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 cold Kohlbergian sort of ladder of
complexity, sophistication, in your moral reasoning? Ways in which this would look. Take somebody and you can
have a Kohlberg 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
preconventional 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 the general
framework of Kohlberg. 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 Kohlberg, doing his
stuff mostly in the 1960s, had the same biases as most
everyone of the time, which was a very disproportionate
share of the studies were done on males
rather than females. The notion that Kohlbergian
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 in [INAUDIBLE] type studies. 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. That's making no sense. I just tied that into knots. Don't listen to
what I just said. Nonetheless, here's
what they have found. People who were 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 Kohlberg 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 OK 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 you 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? That just 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
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. 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 and
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 anti-social 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 it desensitizes. 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? And every parent for
decades has known, of course, what the worry,
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 could now
pull out half a dozen examples of x does not cause whatever,
but it magnifies or blunts preexisting 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 are already predisposed towards that. Next, more aspects
of environment. Here we have the summary of
the classic study that was done a couple of decades ago. Couple at the University of
Toronto named Daly and 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 your likelihood of being
violent or committing a murder, if you were 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
superimposable in these three different cities. One American city, one Canadian
city, one British city. So you could 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
the high testosterone at that point. And one of these sort
of relevant to that, sort of a classic sort of
sound byte in criminology, is one of the leading causes of
a decrease in criminal behavior is people turning age 25. It's a very, very strong
maturational curve. So look at that. Look at 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 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. This is far more important. We now can sort of put
inheritability 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? 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 rhesus 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 with things that the 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 rhesus monkey, then in
the young adulthood you're put 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
there, things of that sort. They had not learned the
appropriate social context. And that's an awful
lot of what's going on. Example of this. And this is one that
I actually observed in my baboons some years ago
and this business about context. Back to baboons and female
baboons, the business there. If you are a high
ranking female, you have far more options to
be aggressive than if you're a low ranking one. You inherit your rank
from your mother. If your mother is
number one in the troop, you, her first daughter,
will be number two. If your mother was number 12
and your her second daughter, you're going to be number 14. It's a hereditary system. And this was some
years ago where it just happened in one of my troops
the highest ranking female who was still fertile,
her mother matriarch was one step above her. But this female,
the highest ranking for a 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
maturation, 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 a 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 there are going to be two old ladies
out in the savanna there doing the same exact
ominous 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 much longer to come through with the
same social dominance system that you would see with
animals in the wild. 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 attack the literature
on parental influence on child development. And her argument was
that peer influences are vastly more powerful than
the field 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 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 the 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 a nice
ironic ending things and she didn't like trip him up
or something like that as she perhaps might
have considered. So Judith Rich Harris. 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 parent's accent. By age four or five
you were 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 Maine 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. 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. 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 a 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. [LAUGHTER] All of the actors who
were chimps ate together. All of the onee-- 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 Rich Harris 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 anti-social 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 households, single mother,
they are more likely to live in a poorer neighborhood. 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 the decreased
crime rate in general? If you have a more conservative
bent which you would emphasize is building of 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 past Roe versus-- past
that first point-- the drop in crime rate was
entirely due to fewer 15 to 30-year-olds. And it just marched out
from there state by state. What their numbers showed when
they did what were currently some pretty fancy
convincing statistics was that Roe versus 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
antisocial 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. Final piece. Final piece in
this, which is now when you look at all
of this development and aggression and
moral whatevers, what does it wind up
looking like in adulthood? What this translates into
is asking the question, how much does one stage of
Kohlbergian 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 dancy
post-conventional transcendent Kohlbergian 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 Kohlberg stage. Having the fancier
Kohlberg stage is a pretty good predictor that
you'll be a moral philosophy professor of an Ivy League
college instead of a state school. If you're stuck in an
earlier Kohlbergian stage, it's a very abstract
academic measure. It is not a predictor
at all over who will do the truly brave,
unexpected moral acts. So what's of 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 is 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 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 in people with
Alzheimer'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. It is predominantly a
phenomenon of the cerebellum. So you look at the people
who do the profoundly brave stepping out of the crowd steps. They're the ones who, regardless
of what their Kohlbergian 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 logical 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 answer
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. You were looking at
an implicit pathway. You were looking
at, I didn't think. Before I knew it I have
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 Greene who did that trolley car study. And here what he did was people
were playing some sort of game where they had to
predict an outcome and they would get a reward
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. And 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. And they had them
in a brain scanner and were able to see
what was going on. So you look at people
who would cheat and what happens
when the signal comes on indicating that it's one of
these sessions where they could get away with cheating. Their frontal cortexes
lit up like crazy. What were they doing? They were wrestling with Satan. They were asking those neurons
to do something or other down in 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 a 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. So now look at the people
who never ever cheated and, of course, one
prediction would be that they have
like frontal neurons poking out of their head
that are so big and energized and their 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,
oh, what if everyone did this? And, oh, it's important
that we have laws. And, oh, what if I get
punished or-- it is simply, before I knew it,
I had jumped in. I didn't even think about it. What I think this suggests
is awful lot of what moral development is about
in 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 them. So we will pick up
on-- what day is it? Wednesday. Today's Wednesday? For more, please visit
us at stanford.edu.
