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Practice English Speaking&Listening with: 20. Aggression IV

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Stanford University.

OK, let's get started.

We pick up with aggression, competition, et cetera.

And where have we gotten to?

We are now just about to leap to, instead

of early environment, early hormonal exposure,

parenatal-- hormones both pre, before and after birth.

Around that time, what do they have

to do with adult behavior in these realms?

So, again, this is tapping into that same concept from the sex

lectures-- organizational hormonal effects,

versus activational.

Organizational early in life, setting up the nervous system

to respond later on to some sort of activational hormonal


So the basic theme that's come through with animal studies

here has been built around, what if you

have females who are prenatally, or perinatally, androgenized,

exposed to high testosterone levels?

And what you see is, basically, the exact same thing

as from the sex lectures, which is

you get a powerful masculinization--

organizational masculinization effect so that later on these

are females who respond to even their low levels

of testosterone in the bloodstream

with increased levels of aggression,

more aggressive play, bunch of measures like that,

less maternal behavior when having offspring-- a pretty

clear literature in terms of prenatal masculinization

of aggressive behavior, as well as sexual behavior.

So, as usual, what about humans?

And we go back to our two diseases

from the other week one was that congenital adrenal hyperplasia

business, that tumor in the mother that produces

vast amounts of, among other things,

an androgen, a testosterone derivative,

which androgenizes the fetus.

Or the case with that drug DES, diethylstilbestrol,

where some women in the '50s took them

for preventing miscarriage, in some cases

had androgenic effect.

Back to the same issue as with the sex

lectures, so what's the behavior of these individuals like?

And, again, people were over that one.

People were really interested in this.

Both of them kind of burst on the scene,

congenital adrenal hyperplasia, and the DES babies,

around the same time lots of people started

studying these kids as they started growing up with a very

simple question here of, are they

going to be more aggressive than typical girls?

And, ultimately, will they be more aggressive women?

And somewhere between the lines, they're

also asking the question, are they

going to be more aggressive than is normal for a typical girl?

So what began to come out of these studies?

First off, some interesting, odd, quirky things-- one

is when you androgenize a female fetus

human, later on as a child she will

have a higher than average IQ.

Whoa, that's kind of interesting.

Stay tuned, it turns out that's not at all interesting.

OK, so that was observed.

Another thing, more of a tendency

towards being left-handed, better spatial skills.

And both of those are attributes that

are more common among males than females.

What else?

That's all that sort of stuff having

to do with ancillary issues.

But now, finally, people were then really focusing

in on the issues of aggression.

And by the time these girls were, I don't know,

10, 12 years old or so, the findings were absolutely clear.

These kids were way, way more aggressive than normal.

How do you know?

Because they were less interested in playing

with dolls than normal girls, because they expressed

less interest in marriage, because they

expressed more interest in having a career some day.

So these were, obviously, over the top, rabid, psychopathic,

androgenized, females because they weren't normal.

They weren't interested in dolls, or marriage,

and were interested in a career.

This was in every textbook starting in the late '60s,

and was still there in textbooks by the mid '80s or so,

endocrinology textbooks.

And somewhere in the early '70s or so,

probably some male endocrinologists kind of

discovered that, you know, wanting

a career if you're female does not count as aggression.

Actually, they came up with an even better term-- assertive


How's that for a term that just summarizes an entire worldview

of gender differences?

OK, so some male endocrinologist finally figured that out.

Or maybe actually they're finally

started being some female endocrinologists who

pointed out this was gibberish.

The entire literature went down the tubes,

had to be started all over.

Oh, wanting a career is not being assertively, dominantly

aggressive if you're female.

So back to stage one on that whole literature, lots of work

since then.

What the literature has generally shown

is the left-handedness is there.

The spatial issue seem to remain.

The higher IQ is there.

What's up with that?

All that's known is as an explanation,

you find an equivalently higher IQ in the parents.

So it's got nothing to do with the androgenization.

There's some sort of selection going on, perhaps

who winds up being in a study like this-- sort of more

educated families.

Who knows what.

But that one turned out to be a red herring.

What about aggression?

Because now there's been populations

of androgenized girls who are now well into adulthood.

What about antisocial behavior?

What about all those sorts of things?

And, in general, what is shown is there's not much going on.

The literature has been pretty ambiguous

in terms of any sort of trends there of different behaviors,

different attitudes, different motivations, et cetera,

in these folks as they grow up.

But suppose what you found was, as adults,

women who had been androgenized as fetuses were now

17 times more likely to start brawls in bar rooms,

to snipe at people from the tops of water

towers, things of that sort.

What would you conclude?

Oh, prenatal testosterone makes you more

aggressive as an adult-- no.

Same confound with these folks as from the sex

lectures the other week, which is these girls were not just

born having been exposed to lots of testosterone in utero,

and doing something or other to their brain.

They were born with, basically, a hermaphroditic profile

of genitals that looked like males, or intersects,

sexually ambiguous genitals.

These were the kids who went through a dozen rounds

of reconstructive surgery in their first half dozen years

of life, their first 10 years of life, in this part of the body

that everyone is interested in, but doesn't quite talk about.

And what's up with that?

Why aren't I normal?

And these, once again, were not girls

who grew up with the only thing being different

about them their prenatal hormone exposure.

Basically makes the whole literature uninterpretable.

So what else in terms of prenatal hormone effects?

Another literature that people have

looked at, which in principle could be extremely

informative, looking at dizygotic twins,

non-identical twins.

So you were a girl.

You're a dizygotic twin.

And you could have a sibling who is either

a sister or a brother.

In other words, you may have spent your time in utero

with your sibling who either did or did not

secrete a certain amount of testosterone during that time.

Do you see any sort of masculinization

of aspects of aggressive behavior

in girls who are dizygotic twins with a male sibling

rather than a female one?

And what you wind up seeing is these kids show,

on the average, more aggressive play in childhood,

more-- here's the jargony term-- more rough

and tumble play, more interest in cars, mechanical things

like that, less interest in stuffed animals, in dolls--

small effect, very small effect.

Nonetheless, it suggests that this is another realm where

a little bit of prenatal exposure to testosterone

will change the behavioral profile.

Except there's a confound in these studies, which

is if you were a girl and you have an identical twin who

is a boy, you are in the Guinness Book of Records.

OK, let's start that one.

If you are a girl and you have a non-identical twin--

that's how it works, OK.

I knew I should have checked the notes before coming.

So you've got a non-identical twin who is a boy.

Not only do you spend your prenatal environment

being awash in some of his dribbling hormones,

but you grow up with him.

And girls who grow up with boys as brothers-- as

opposed to plants as brothers.

Whoa, what is happening here?

OK, being a girl growing up with brother brothers increases

the likelihood of rough and tumble play, because that's

what you do with your brother-- once again,

uninterpretable literature.

Generally, what you see is very, very clear

cut androgenization of aggressive behavior prenatal

testosterone when you're looking at rodents.

By the time you're looking at primates, some pretty strong

patterns but nowhere near as dramatic as in rodent

species looked at.

By the time you look at humans, maybe just some hints,

but that at the most.

Of the most interesting realms, literatures,

where people have been thinking about prenatal testosterone

exposure is work of a guy in the UK

at Oxford named Simon Baron-Cohen.

And what he is, is basically the world's expert on autism.

And he has developed what is called the hyper male

hypothesis of autism.

For starters, there's a very, very big gender skew

in autism-- far more frequent among boys than girls,

among males than females.

And what Baron-Cohen has done a lot of work on over the years

is first looking at a whole array

of sex differences between normal human males and females.

Sex differences, some of it's the finger ratio stuff.

Some of it is neural anatomy, some

of those structural differences in the brain,

having to do with that.

Some of it is functional spatial skills versus language skills.

Some of it is problem solving.

And there is a gender difference that

tends to come through with that on the average in that boys,

males, men, take more analytical approaches

to social problem solving.

Girls, women, females, take more empathic ones.

So that's a difference.

OK, so he studied all sorts of stuff

like that, and obviously with hormones as well--

all sorts of really subtle interesting physical

differences, whole array of these.

And what he has shown is that individuals with autism,

regardless of their sex, tend to have

even more exaggerated versions of

those male typical profiles-- the finger length,

the analytical focus at the cost of social empathy,

social affiliation, the very strong spatial skills,

whole bunch of those.

So he's made a fairly convincing argument,

I think, that is good.

Something's going on in terms of prenatal androgenization,

perhaps, which produces a more masculinized profile, which

taken to its extreme winds up being autism.

In other words, normal male behavior

is just skating on thin ice before going

into this whole realm of sort of dysfunctional socialization.

Lots of stuff with that, as we'll

see next week some very interesting differences

in the wiring of the cortex of people with autism.

And males show that same thing, just not as extreme.

OK, interesting footnote thing-- Simon Baron-Cohen

is apparently the cousin of Sasha Baron-Cohen of Borat,

which suggests that must be one interesting family when they

get together for the holidays.

OK, moving back one more box, however-- no,

I'm not going to do that.

OK, moving back one more box.

Now, instead of perinatal hormone stuff,

early environment, what about genes?

What about genes?

What do genes have to do with aggression, competition,

cooperation, empathy, et cetera?

It used to be not that long ago if you even raised

the possibility that there were genetic elements to aggression,

you would be hounded out of certain realms

of social science.

It was viewed as wildly incorrect, wildly offensive,

hidden agendas out the wazoo.

For some reason, this began to pass in the early '90s or so.

There were studies in the mid '80s, conferences

in the mid '80s, where there were protests.

They were picketed, because in this meeting that

was considering the sociology of aggression,

the this of aggression, the biology,

the genetics, the inclusion of it,

was the grounds for the picketing.

A number of those were canceled by the National Institutes

of Health under public pressure of certain interest groups, all

of that.

It used to be viewed as outrageously offensive,

the notion that genes have anything to do with aggression.

So there's two ways of showing that that's wrong.

The first is to sit somebody down

and make them go through the last 15 lectures in this class.

Or the other is to reflect on the fact

that you would leave a three-year-old

in the care of a basset hound, but not with a pit bull.

Oh, there are breed-specific differences in behavior.

That, if nothing else, is a demonstration of it,

that dog breeds have been bred for 20,000 years or so

to differ in levels of aggression,

in levels of affiliation, all of that.

People who for some bizarre reason follow bullfighting,

there are lines of bulls, different ranches of Spain

in Mexico, where they have been famous

for centuries for the particular fighting style of the bulls

that they breed.

Genes have something to do with it.

Of course they do, because hormones

have something to do with it.

And because receptors, and because enzymes,

and everything with that, it is impossible to have talked

about any of this stuff on the far right of the chart

without invoking genes-- a ludicrous view.

So what is known about the relevance of genes

to aspects of aggressive behavior?

First off, at this stage, there's

been a whole bunch of studies-- many of them winding up

in some very visible journals-- where people find

a gene implicating it in abnormal levels of aggression,

one of those sorts of behaviors.

Typical strategy-- these might be genetically engineered

animals to remove that gene.

Or there might be a spontaneous mutation.

And all of these report that these

are animals with a whole bunch of these mutations,

that these are animals with abnormally

high levels of aggression.

That's kind of a clean experiment.

If you go in-- and thanks to a mutation, or chopping out

one particular gene, and now you've

got a lot more aggression in that individual.

That kind of suggests that that gene

has something to do with aggression, perhaps

a whole lot.

What are all the problems with that?

Other ways that that gene could be

affecting behavior, which indirectly winds up

getting to aggression.

One possibility-- what if that's a gene that

is relevant to impulsivity?

And this is an individual who, if you

gave the mouse a different realm of tests,

would be shouting its love to the world at an impusively

high rate, just as it's being aggressive

at an impulsively high rate.

Maybe it's a gene having to do with impulsivity.

Maybe it's a gene having to do with one of the things

we heard in the last lecture.

What are the environmental releasing stimuli

that cause aggression to occur?

What's one of the most reliable ones?


Oh, it turned out a number of these strains

of mice that were identified with a gene knock-out.

That here's a gene which can cause aggression.

It turned out that these were genes

that made animals that were much more sensitive to pain.

And they were more likely in a pain state

to displace aggression on to something else.

Or, as was shown in some of these,

these were animals who were more aggressive.

But they were also more affiliative.

And they were more everything.

Their generic level of arousal was a lot higher.

So all these caveats, an awful lot of the genes

that popped up in the first generation of those sorts

of studies that looked solid, that were replicated,

a lot of them instead had to do with indirect routes,

rather than directly with aggression itself.

So what about the genes that have held up?

And in the really plausible candidate ones,

we've covered some of these are already--

the serotonin synthesis genes, and the serotonin receptor

genes, and the dopamine receptor genes.

All of those have been very solidly implicated, really

careful research, the molecular biologists teaming up

with behaviorists knew what they were

doing-- a genetic component.

And what you know by now that is absolutely about

is this figure again.

That's the case with all of these genes.

Oh my God, it's not genes causing aggression.

We know exactly this one, modulation,

all that stuff, again depending on the environment.

And the environment in the realm of genes

relevant to aggression, the environment

is overwhelmingly about abuse and stress early in life.

So that's about as far as genes will get you there,

which is plenty good, because this

is exactly how the genes should be relevant to behavior.

This is how all genes are relevant to behavior.

Remember our ultimate punchline from the behavior of genetics--

at the end of the day, it actually

doesn't make any sense to ever say what any gene does,

only what it does in the following

range of environments.

In terms of that, what you are beginning to find

is this still sort of growing field which

is beginning to look at differences in these genotypes,

these different versions of these genes,

in different populations, in different cultures.

And that's just beginning as a literature.

I'm not impressed enough with the findings

yet that it's worth passing them on.

But that is going to be a very interesting field.

Finally, there's always this puzzle with any of these of,

oh, you've got some gene that's predisposing you

towards being aggressive if you were abused in childhood.

We still know nothing in terms of that gene.

That gene has got no predictive power

as to whether this will thus be someone who grows up and is

a sociopathic murderer.

Or if this is someone who grows up and is just an unbelievably

nasty Monopoly player.

That factor, again, that same deal-- oh,

major frontal cortical damage, disinhibition.

You can't regulate your behavior.

No science in terms of the neurobiology as to why

one turns into a serial murder, and the other one who

doesn't catch clues that the family wants to eat dinner.

Again, it's the same puzzle over and over.

And, again, you could begin to guess what the differences are

going to be.

Problems in some of these realms with these aggressive genes,

and different upbringings, different stabilities

and families, different relationships, different role

models, you can be off and running with that one.

One final domain in genes and aggression--

and only a handful of you the other lecture

knew who that guy Charles Whitman

was, who was the guy who climbed up

the Texas tower, all of that.

OK, so here's another chance to score points

in the mass murderer realm.

How many people have ever heard of a guy named Richard Speck?

Wow, very few-- no hands.


No, that's a bottle going up, not a hand.

Richard Speck was once one of the most notorious people

in America.

Richard Speck was a nightmare sociopath

who in 1968 committed a crime that just

stunned the entire country.

People wrote songs about it.

It was just as brutal as one could imagine.

He broke into the apartment of eight nurses

living in Chicago, eight student nurses,

and slaughtered them all.

And this was shocking on a level that's hard to describe.

Richard Speck was the nightmare sociopathic murderer.

So he gets sent off to prison eventually for life.

And in the process at some point or other,

he's getting some physical exam.

Somebody takes a blood sample something.

And a lab technician notices something

interesting in his blood, examining

the chareotypes, the structures, of his chromosomes.

And they discovered that he had an extremely rare

chromosomal abnormality.

Females, XX, males, XY-- every now

and then you get somebody where something screws up.

And what you now get is XYY.

You get an extra Y chromosome.

And, suddenly, this had to be the explanation

for what was going on.

Males are a total pain in the ass all over the world.

And they've got those Y chromosomes.

Oh my God.

The guy has two Y chromosomes in every single cell.

This explains it.

And this suddenly started this hysteria

about violence and the XYY male.

Senators were bellowing in Congress

about how we needed to screen our schoolteachers to make

sure none of the men had XYY profiles.

The military was all set to start testing recruits for XYY.

Although it's not clear if that would get you in or would

that get you out, how that one worked.

But they were suddenly interested.

Tons of work went into it, this flurry

of excitement, special funding.

We need to be on top of this.

And by the early '70s, what was clear was

there was no relationship whatsoever.

So that one went down the tubes.

And then one of those ironic ending departments,

it was eventually discovered that a lab technician had

blown, had done the chareotyping wrong.

And he really wasn't an XYY male,

despite that lab technician then having called up

the newspapers.

He was a normal XY sociopathic male.

So that one was up there for a while,

more realms of don't overvalue the genetic evidence.

So that shifts us now one step further back.

And now begin to look at whole populations--

whole populations not yet on the genetic evolutionary level.

But what do things like ecology have

to do with levels of aggression?

What does culture have to do with it?

What does factors like that?

And there's a really interesting array of findings out there.

First off, one important dichotomy

when looking at traditional human cultures

is how people make their living.

And the one that's pertinent here

is the dichotomy between pastoralist people

and everybody else.

Pastoralist people, nomadic pastoralists people, these

are cow people.

These are people who wander around with their goats,

or their camels.

These are the shepherds, in contrast

to traditional agriculturalists, or far rarer

traditional hunter-gatherers-- so nomadic pastoralists

versus everyone else.

And what a boatload of anthropology has shown

is nomadic pastoralists have higher rates of violence

both within group and between group.

Nomadic pastoralists are vastly more likely than other groups

to have standing armies, warrior classes,

to have leadership be derived from people

who have had the most success as a warrior,

to have myths built around their religion that success in war,

violent acclaim in war, is your gateway to heaven,

or whatever afterlife is viewed as most desirable.

This is a consistent finding.

Lots and lots of these cultures, nomadic pastoralists

are the ones who came up with warfare on a certain level,

and warrior classes.

And this makes perfect sense, because one feature

of being a nomadic pastoralist is you're nomadic.

At certain times of the year, there's

one subset of the whole village who's off 15 miles

away where there's some good grazing.

Another group is on the other side.

And what this sets you up for is something that farmers never

have to worry about.

Somebody can't come and rustle your farm away at night.

But people can come and steal all your animals.

Warrior classes, so that at any given point,

if people are dispersed, there is still a designated age group

of individuals who are out there to defend the collective herds

of the group.

So you see that.

In the United States, where that has had

an interesting manifestation is where

people settled in the original 13 colonies,

from which part of the United Kingdom.

And some very influential studies, really interesting

creative ones, pointing out that the American South

was disproportionately settled by sheep people

from the northern ends of the British Isles--

in other words, nomadic pastoralists.

Shifting to another realm of anthropological designation,

these are people who disproportionately have

come from cultures of honor.

Cultures of honor, where people are

willing to kill over very symbolic slights rather

than over material conflicts, where there

are vendettas within the group, there

are vendettas between groups, where

it is honorific to have to avenge

a death, which you do not necessarily

find in agriculturalists.

Cultures of honor, and that goes hand-in-hand

with nomadic pastoralism.

And what you get there, typically,

are very clear rules about enforced hospitality

for guests, and very clear rules of the circumstances

of aggression, retributive ones, over symbolic affronts.

And that's really clear difference regionally

in this country.

Interesting sociologist, University of Michigan,

named Richard Nesbett.

And he grew up in the South.

And I actually heard him once give a talk

where he talks about how when he was about 18 or so,

he left the South for the first time

and joined this very strange culture at Harvard

University as an undergraduate.

And he was dumbfounded by how different of a world this was.

People didn't shoot relatives at picnics,

at barbecues, which sounded totally facetious.

But when you look at the higher crime

rates in the American South, it is not

occurring in urban areas.

Urban crime is roughly equivalent

all throughout the United States.

It is not due to higher rates of what

they call 7-Eleven robberies, which is just material

gain, a robbery of that sort.

It is murders of honor.

It is people who know each other at social settings,

people who have some insult, have something that has nothing

to do with material wealth.

This is where the disproportionate violence comes

from in the American South.

And prompted by that, Nesbett did

one of the all-time interesting studies, this famous, amazing


So he's at the University of Michigan.

And he recruits student volunteers

who believe they're going in to do a hopscotch test,

or some such thing.

And they're going in.

But he made a point of finding out where everyone came from.

And he got a fairly even distribution

between the relatively few students in Michigan

from the American South, and then students

from the more traditional North.

So we get into the psych building, each individual who's

coming for their appointment.

And they take the elevator.

And they come out.

And they walk down the hall.

And this is where the experiment happens.

Nesbett has somebody working on the project--

a confederate on the project, I say making a lame pun, OK.

So a confederate on the project, a person

working on the project.

And this was a big, beefy guy.

And the whole idea was that this big, beefy guy

was going to do something insulting

to this individual walking down the hallway, all male.

Here's what they did.

They clearly did a lot of thinking

in designing this study, in terms of what single word

this person was going to say.

And this is what he wound up saying.

The volunteer would be walking down the hall.

Here comes this big, beefy guy moving fast.

And as he comes by him, bumps into him with his shoulder,

walks past, and says, watch it, asshole, and then disappears.

Volunteer comes in to start their study,

and quickly they look at blood pressure, and heart rate,

and stress hormone levels, and testosterone levels,

and get a typical participant in this study from the North.

And they come in.

And they're a little bit irritated, and what a jerk,

and all of that.

And it's all over with two minutes later.

Get people from the American South,

on the average massive stress response, hypertension,

elevated testosterone levels, big regional differences.

These are some of the physiological pictures

of cultures of honor.

What else?

What other interesting things about ecosystems, or ecology,

or cultural aspects?

Another dichotomy that is really consistent-- and this one

maps pretty readily on that pastoralist versus everybody

else-- the sorts of cultures and the level of violence

that are generated in cultures that live

in deserts versus rain forests.

And, once again, deserts are where

you are far more likely to find nomadic pastoralists, rain

forests, hunter-gatherers, mixture of hunter-gatherers,

small farm agriculturists-- two totally different worlds

of occupations.

And what you see is far higher rates

of violence within group and between groups

in desert dwellers.

And that maps very logically onto pastoralists

versus everybody else.

Desert dwellers, open savanna grasslands,

that's where you see the warrior classes.

That's where you see raiding of other tribes.

That's where you get that pattern, virtually none

among the hunter-gatherers.

I might point out something which

will become sort of focused on more in a lecture in about

a week or so.

I should point out that desert dweller nomadic pastoralists

are also the cultures on this planet that

invented monotheism.

Consistent difference-- desert dwellers

tend more towards monotheism.

And it was invented by desert nomadic pastoralists.

Rainforest cultures far disproportionately

tend to be polytheistic.

And this is not remotely surprising.

If you're living in a rainforest and there's

10,000 different types of edible plants around there,

it doesn't take a lot of work to come up with the notion

that there's lots of different spirits and gods out there.

What the desert it is about is one, singular baked truth there

of surviving.

That's where monotheism was born.

Monotheism, historically, is more

associated with cultures that invented warfare, and invented

warrior classes, and raiding, and things of that sort.

That's kind of interesting.

OK, moving on, more cultural differences-- one of the great,

great predictors of having a society with lots of violence

in it, and lots of warfare elsewhere,

is a culture that has rots of cultural myths

of victimization.

We have been screwed historically, because of this,

this, and this, and coupled with that an ethos of not

turning the other cheek, but instead of retribution.

Cultures that have strong histories

and or myths of victimization, and strong values

built around retribution are extremely violent societies,

and often really bad news as neighbors.

What else?

Amazing study that got published about a year ago,

which is on the recommended reading list.

This is not required.

But this was a deeply interesting study.


Was one of those game theory studies.

It was a game a little bit like prisoner's

dilemma-- not exactly the same, but the same sort of notions

that you could be very generous in your game playing style.

You could be absolutely rationally fair.

You could be exploited, a whole range of possibilities.

What these guys did in this study

was take scads of people from 40 different countries.

No they didn't, from 16, 19, they

took from a bunch of different countries.

And just to control for things, all of the subjects

were university students.

So you're selecting for a fairly homogeneous bunch,

both within group and across these different countries.

And what they did was they had people play these games.

And they had the option for what is called altruistic punishing,

which we will hear more about in a little while, which is you

have the option to expend some of your resources--

your points, your chips, whatever--

you can spend to punish the other individual for cheating.

And the question, of course, becomes,

how much are you willing to spend to punish somebody

when they've been cheating against you,

when they've been stingy, when they haven't reciprocated,

all of that?

First finding, which is everybody

across all the countries averaged out

to the same rate, the percentage of resources

that someone is willing to expend

on punishing a cheater-- so no particular cultural differences


But then they identified another interesting realm

of game behavior here, which they called antisocial

punishment, which is where it's not

that you are expending some of your resources to punish

somebody for having cheated.

It's where you're expending resources

to punish someone for having been overly generous.

And that pops up in certain sorts of games.

It is not terribly common when it's

the person who is choosing with their opponent.

But when you have a third party, you

have no cultural differences at the rate at which they

are willing to punish cheaters.

But here's where the differences came

then, the rate at which people would punish

unexpectedly generous players.

And you got a big spread.

The lowest rate at which this happened

was, nicely, as it turned out, people

from this country, which is kind of nice, people from England.

And, of course, who else?

The ever-useful Scandinavians with their powerhouses

of the cells and their other cliches all set.

So the Scandinavians come through yet again.

But, for once, we're able to hang out with them

and actually count as having a good profile--

the lowest rates of people being willing to do

this nutso anti-social punishing in those countries.

In between rates-- a number of Middle Eastern countries,

a large number of Eastern Bloc countries, in other words

Slavic ones that used to be part of the Soviet Union, Korea,

and turkey.

Those were the middle ones.

Which ones had the worst rates?

I will just read the two countries here

that were way up there, a big gap between them

and the rest of the countries.

One was Greece.

And the other were the Arabic Emirates on the Saudi Arabian

Peninsula, where people are willing to spend more

to do anti-social punishing than they

are willing to spend to punish cheaters,

extraordinary finding.

People from Muscat, which was where the university was,

those students were more willing to punish someone

for being unexpectedly generous than for somebody

cheating on a game theory social contract-- totally amazing.

So what's that about?

When they actually question people,

you see things with people from there

along the lines of, if people start

doing that, of being all generous like that,

it's just going to up the ante for everybody.

Everybody's going to have to start doing that.

That's an interesting piece of reasoning.

But when you look at a larger level, what these researchers

then showed was a predictor across all

these different societies of the rate

of this anti-social punishment levels of trust in the society.

Some standard metrics used by sociologists

who were interested in this concept of social capital--

how much social trust there is in the society, how

much participation there is, how much of a sense of efficacy.

And what you see is the lower the levels

of social capital in these societies,

the higher the rates of this anti-social punishment, totally

interesting study.

Next in the realm of culture, what

are people doing these days, what

is sort of the science and the research these days,

trying to make sense of terrorism,

and the sort of cultures that give rise to them,

and the sort of ideologies that give rise to them?

A number of basic dichotomies-- one

is a camp that views it as always

abnormal sociopathic behavior.

Another is a camp that just views terrorism

as extremes of ideology.

The first one is much more about individual dysfunction--

oh, this is a neuropsychiatric problem, perhaps.

The second one is one more a feature

of cultures that have extremely strong ideologies.

So that's one division in there as to how to think

about it in the community.

Another division is really interesting.

And it's one my reading of this literature

that has totally thrown people in the field for a loop.

Forever, there has been a profile,

a demographic and psychological profile,

of individuals who are terrorists,

all the way back to the people who did the Boston Tea

Party in this country, the IRA.

All sorts of stuff like that, the Haganah, which

was in Israel, terrorist acts before independence,

studied in a whole bunch of these

that there tends to be a rather consistent profile

of these individuals who would be terrorists.

Young, male, socially isolated, socially unaffiliated in terms

of relationships, relatively uneducated background,

history of childhood abuse, and another factor which has just

completely slipped my mind.

What was it?

Oh you all know.

OK, so that's exactly what you find in these folks--

a picture of isolated sociopathic individuals

who already have a history of anti-social behavior.

These are people who, if they hadn't stumbled

into this cause, would be spending

their time mugging old ladies.

That would be that profile.

And you look at these various groups.

And that has been a consistent one.

Terrorism in the recent years, particularly Middle Eastern

fundamentalist, is a completely different profile.

It is not young men.

It tends to be educated, well-off people

in their thirties and forties, overwhelmingly middle class

or upper class backgrounds.

Next, it's not just middle-aged males.

It's females.

It's women to a much higher extent than seen

in any previous sort of population

dealing with terrorism.

Next what you see is these are individuals

who, on the average, tend not to have

had any direct exposure to the suppression

that they are fighting against.

As opposed to the sociopathic model, a classic picture

with IRA gunman, the father was taken away by the whoevers,

shot, never came back again.

And they were passed on the family mantle.

The current picture is a very different oe--

no direct experience of the persecution.

Finally, tending not to have particularly high levels

of religiosity, and this is this very contemporary profile

where you get these 40-year-old engineers who are suicide

bombers, where they go home.

They say goodbye to their families.

They make a video tape sort of wishing everybody well.

And after having quit their job and paying the rent one

extra month, and off they go and blow themselves up.

People, I sense, in the field haven't a clue

how to make sense of what this is about, very new,

challenging feature.

One interpretation, one is of a school

pushed by people like Phil Zimbardo

here in the psychology department, incredibly

influential psychologist, who as a general theme over the years

has argued for the stance that under the right circumstances,

under the right coercive circumstances,

virtually anybody could do anything that is appalling.

Zimbardo, who did the famed Stanford prison study.

The other view is, OK, this isn't a lesson

that anybody could wind up being this violent if, look at them.

They're an engineer.

And they've got a master's degree, and all of that.

Instead, it is simply an outcome of a lot of what terrorism

is about these days, a very novel world

of international terrorism.

Rather than within country, suddenly you

have a world of people who need to be able to do things

like get passports, and fly elsewhere, and be

able to navigate customs, and things of that sort.

It is suddenly selecting for a more sophisticated population

of individuals.

You know, the jury's out on all of this.

But this seems to be a very challenging thing

for that field.

OK, so now this allows us to push one step further back.

I'm going to skip over a few things there.

Now, insofar as we are looking at culture,

and insofar as we have looked at anthropological differences,

and insofar as we have looked at anything having

to do with genes, we now have to talk about evolution,

because that's where the genes came from, of course.

So in first pass, it's absolutely simple

to understand what evolution has to do with aggression, which

is evolution selects for higher and higher levels of aggression

because that's what you need to succeed.

Unless you grew up watching certain types of television

programs, in which case evolution selects

for no aggression occurring because animals

behave for the good of the species.

So sorting through that, beginning now

to apply some of our foundations from that world,

individual selection, kin selection, reciprocal altruism,

and the modern version of group selection.

So where do these play out?

First, how do these play out in terms

of increasing the likelihood of aggression and antisocial


Individual selection, males, that is absolutely simple.

In every culture on this planet, and in the vast majority

of social species that have been looked at,

the majority, the major cause of aggression

in that society or species is male male violence

over reproductive access to females.

That is close to a universal.

That is the most common form motivator

of violence on this planet, humans and otherwise.

So that one's easy to come up with,

in terms of obvious stuff.

One classic study, insanely controversial one,

that appeared to be the landmark demonstration of some

of the same in humans-- traditional tribe,

hunter-gatherer down in Venezuela in the Amazon

called the Yanomamo who have been

the darlings of high testosterone male

anthropologists for decades.

These have been intensely studied people, many decades

now, predominantly by an anthropologist named

Napoleon Chagnon, who is now emeritus at Santa Barbara.

But he has been a major figure in anthropology

for a long time.

And these people are insanely aggressive, incredibly high

rates of violence between groups, within groups.

Sufficiently so that the written monographs

of the Yanamamo, with titles like Yanamamo,

the fierce people, things of that sort.

And about 15 years ago, Chagnon published a paper

in Science using decade's worth of data

showing that the more people, particular men in this society,

in this tribe, the more people you have killed on the average,

the higher your reproductive success

That's it.

That's it.

That's everything right there.

That's Darwin all over the place.

Just play it out over time.

And this is dramatic selection in a traditional human society,

the reproductive rewards of violence and murder.

Very major, influential study, picked up

by all the newspapers.

And it has been completely mired in controversy

ever since, all sorts of ethical attacks on Chagnon,

most of which that have not stuck,

but some really, really telling dissections of the work,

ripping it apart on statistical grounds.

I don't think it's actually for real.

But that as easily interpreted within that framework.

Then more realms of violence, individual selection,

orangutans raping each, rape in other species,

rape among humans, which of course brings up

the question of whether rape is more about passing

on copies of your genes, or more about power and subjugation.

And the overwhelming sense in the field

is it's about the latter.

It does not have a whole lot to do with a world

where you have to start counting numbers of copies of genes,

and thinking about adaptiveness of strategies.

Next, individual selection, explaining another realm

of violence-- in most cultures, and in an awful lot

of species looked at, the second leading cause of violence

is males attacking females over denial of sexual access.

And this is amazingly common all over the place,

the second leading cause of violence

on this planet across humans and different cultures,

and obvious easy individual selection explanation there.

Finally, another realm individual selection,

the world of female female competition,

and infanticide, competitive infanticide.

We know how to run all of those.

So lots of reasons within the framework

of individual selection to see where you are

increasing rates of aggression.

Next, kin selection-- you're going to know that one as well.

Two brothers or eight cousins, and that whole strategy,

and that's why related individuals

cooperate with each other in circumstances of aggression.

Chimpanzees-- chimps are function

where females are the ones who pick up at puberty

and go elsewhere.

So all of the adult males in a chimp group

are brothers, first cousins, things of that sort.

And, thus, you get one of the outcomes

of that, high levels of male male cooperation.

And as we heard, that has been reported by Goodall and others

to result in things that look absolutely

like organized warfare and genocide,

eradicating all the males in a group in the next valley

over, purely along kinship lines.

What else?

Other primates, old world primates, monkeys like baboons,

aggression is very much between lineages than within,

same exact kin selection sort of arguments.

So what happens when you get to humans?

Things get more complicated, of course.

The first one being that a relative, relatives,

is a relative term, in that it is a sliding scale.

Wonderful quote to that effect, a Bedouin quote,

which is, it's my brothers, my cousins, and I

against the world.

And it's my brothers and I against my cousins.

As in, who counts as an us, and who counts as a

them is a sliding measure.

It is a relative measure.

What you see is by the time you get

to humans capacity for very rapid shifts of us/them

along the lines of relatedness.

Now, one of the readings, which I can't remember now

if I actually did stick into an assignment,

but one of the readings looks at the classic social biological

interpretation of making sense of aggression

along the lines of kin selection.

What do you make of child abuse?

What do you make of homicidal parents, damaging parents?

How do you make sense of that in a, are you out of your mind?

This is copies of your genes there, the challenges to that.

And this is a couple, Daley and Wilson, University of Toronto,

I think, who have for decades been working

in this area showing things like a child is

more likely to be abused by a stepfather

than a biological father.

Wonder what that's about?

Kin selection, that's easy.

A child is more likely to be abused

by a paternal grandparent than a maternal one.

Kin selection explanation-- more certainty of paternity

when something is going through a female line.

So they've been all these studies

showing that degree of relatedness

explains a fair amount of the variability in patterns

of violence within families.

Problems with it-- two problems, one

is there's been a lot of failure of replications

in other societies.

The Scandinavians, for example, don't see that pattern

when they study it.

The other is there's alternative models.

There's economic models, for example.

When times get tough in terms of displacement,

family violence increases.

Families with stepfathers, on the average,

are under more economic duress than families

with biological fathers, greater likelihood of violence there.

It is a very uncontrolled literature.

That is sort of viewed as in the classic,

and in other people's view, the most ideologically most extreme

way in which social biologists think about something as

bizarre and challenging as close relatives killing each other.

One final realm, which is in terms of this us/them stuff,

the point here being, how do you decide who is an us and them?

And suddenly, we're in our world of ethology.

Do we make some us/them dichotomies more easily

than others?

Do we have prepared learning to see

some differences as more salient than others in us/thems?

That remains an immensely controversial subject

in terms of what are the natural categories that young kids

divide people up by?

Are kids colorblind in terms of skin color?

Are kids blind in terms of body types,

in terms of some such things?

Lots of work in this area, how unnatural

are some of the us/them dichotomies

that we tend to come up with?

Stay tuned about 20 minutes, and you will see not very natural

at all.

As soon as you get to humans, all this social biology

stuff with kin selection is interesting, but as

soon as you get to humans you get to something vastly more

interesting and important.

Back to our recognizing relatives realm--

the business of how we interact not with our relatives,

but with people who we feel as close to as if they

are relatives-- pseudo kinship.

And what you see in culture after culture

is brilliant manipulative skills on the part of powers that

be to make some non-relatives feel more related to each other

than they actually are.

What's this about?

This is military indoctrination.

The whole point, or one of the main points,

of military training early on is to get

people to become a band of brothers,

a band of pseudo kinshipped relatives,

to increase the cooperativity later on,

to increase the odds that you are

willing to give up your life for the person next to you.

Culture after culture is great at doing this.

Warrior cultures-- for example, the Maasai in East Africa,

they have a warrior stage when you're 15,

you go become a warrior, roughly 15.

And you stay that way for a decade.

And you protect the cows.

And you raid the neighbors.

And once you're 25, you become an elder

and get married then to a 13-year-old.

But what you've got there is the entire structure of warrior

life is built around pseudo kinship.

They live separately from everybody else.

They use kinship terms for each other.

For the rest of their lives, their wife

will refer to somebody from their warrior class

as her brother-in-law.

Warriors are not allowed to eat their own food.

They can only share their food with another warrior,

all built around generating pseudo kinship.

Other version, that other more industrialized version,

the Israeli Military, for example,

allows kids when they are signing up after high school

to join particular units as a group, a group of friends

from their high school, increasing the pseudo kinship

element there.

More of that-- something that was absolutely unprecedented

when you look at the difference between kinship and pseudo


World War II, United States hugely heterogeneous country,

obviously, blah, blah, melting pot, all of that.

And World War II was sort of the peak of that picture.

And what you got in many, many fighting units

was something straight out of central casting

in these inspirational movies.

There's McCarthy from Boston, and Sapiola from Philadelphia,

and Kewalski from Chicago, and then the Southern guy,

and the Jewish guy from who knows where.

And they're all together.

And they're a fighting unit of American unity,

and all of that.

And what does that produce?

Something that was virtually unprecedented in warfare.

If you were an American soldier in World War II

and you were of German-American or German ancestry,

you would, on the average, almost certainly

share more genes in common with the people you were trying

to kill than the people you were willing to give up

your life for, as you had classically heterogeneous

troops on the American side-- completely unprecedented,

so this business of pseudo kinship.

Historically, Vietnam was apparently

a major failure of military pseudo kinship mechanisms,

in that something unprecedented was done there,

which was people were not kept in stable fighting units.

Instead, people were constantly shuttling in and out.

And you would get these nutty circumstances, apparently,

where you'd be there in the middle of the firefight.

And the person over here is some kid who showed up this morning.

And the guy here, if he survives this,

he's shipping out home to Hawaii tonight.

And who feels like a brother?

No one.

Vietnam had an unmatched degree of breaking of unity of troops.

Why was that done in Vietnam?

Something that kept happening.

As soon as they allowed units to remain more stable,

the rates at which soldiers were shooting their officers

would go way up.

So another, perhaps, version of cooperation.

Hand-in-hand with the pseudo kinship

is, of course, the flip side, pseudo speciation,

the mechanisms, the psychological, the propagandist

mechanisms that are available to make them seem as

different from you as possible.

Not just different sorts of people,

but pseudo speciation-- they are so different they hardly

even count as humans.

It doesn't count as much when you kill them.

And endless realms of that World War II propaganda

in the United States about various

ethnicities that we were fighting

against pseudo speciating, various genocides, the Rwandan


The sort of call to arms there was kill the cockroaches,

kill the cockroaches, the Hutu tribes killing the Tutsis


And this was pseudo speciation.

Let me give you an amazing example which

occurred in this country not all that long ago around 1990.

An astonishing piece of pseudo speciation

that happened in this country-- 1990, first Gulf War.

Kuwait was drilling oil from underneath the Iraq's land.

Iraq got pissed off, invaded them.

And, suddenly, we had the first Gulf War.

The United States goes in there to drive the Iraqis out

of Kuwait.

And ultimately has to make the decision

of whether to follow them into Iraq and overthrow

Saddam Hussein.

And that wasn't done.

But so this war going on.

Very early on, it was absolutely clear

where it was heading, which was that the diplomacy was failing.

And the United States was beginning

to pull together a coalition of various countries

that would be a unified force fighting against Iraq.

But it had not yet been authorized by US Congress

as an act of war.

Suddenly, into this came a woman,

a refugee from Kuwait City.

Refugee, she was a nurse who worked in a hospital there.

She had managed to get out of Kuwait

after the Iraqis had invaded.

And she came and testified in Congress

about an appalling thing that she had witnessed,

which was when the Iraqis came in and took over

their hospital, not only did they steal all the supplies.

They took the newborn infants out of the incubators

and left them out to die, and shipped the incubators back

to Iraq.

Everyone was flabbergasted by this.

This was every newspaper in the country, everybody

learned about this.

Everybody suddenly learned, my God, they leave babies out

to die.

These people hardly count as human.

And, critically, that war was authorized by Congress

by just a couple of votes of senators.

And at least a half dozen of them

cited this incident in helping them decide and this was

something that had to be done.

This was a deciding factor in us going to that war.

And the remarkable thing is, it never happened.

The nurse was not a nurse from Kuwait City.

She was the niece of the Kuwaiti ambassador

to the United States.

She had been trained by a public relations

firm paid for by the US government

to make up this story.

And she sat in our Congress on live TV

in front of the entire country, lied like crazy.

And we went into that war with a 92% approval rate-- one

gigantic piece of pseudo speciation.

My God, they leave babies out to die.

It will hardly count killing them.

They're hardly even human.

And the coverage of when it was revealed what was actually

going on with this person didn't come anywhere close

to front page in any newspaper in the country, buried down

in there.

Virtually the entire country came out of that incident

having learned how inhumane, those people

hardly count as human.

OK, five minute break.

Our principles of individual selection,

kin selection, reciprocal altruism,

begin to give us insight into circumstances where evolution

should select for more aggression,

for more warfare along those lines.

Now, the flip side-- what is it in the realms

of these basic building blocks of evolution

that will push for more cooperation, more empathy, more

affiliation, less violence?

Individual selection level-- we already

know some of these examples, which

is that whole world of alternative male strategies,

that whole world of sometimes if you're a male baboon,

you could pass on lots of copies of your genes

by fighting like mad and being high ranking.

And sometimes it's by bypassing all of that

and being the nice guy, having an affiliative relationship,

and female choice being the thing that

winds up increasing the number of copies of your genes.

So the possibilities of alternative mating strategies,

the possibilities of, of course, parental behavior,

and all we need to do there is switch over

to the world of South American pair bonding monkeys.

And those are not animals with particularly high rates

of aggression.

So all of those are circumstances

where that could potentially be perfectly genetically

viable alternatives to natural selection

selects for higher degrees of violence

because it passes on more copies of your genes.

OK, kin selection-- so we've just gone through kin selection

insofar as it can generate pseudo kinship

and make you a better, more murderous soldier

who is more willing to give up your life

for your band of brothers.

And conversely, pseudo speciation,

they hardly even count as humans.

The flip side, of course, ways in which the human capacity

for pseudo kinship can be used to decrease violence,

and to make things more peaceable, and to make people

feel more connected with each other.

This is a ritual in all sorts of societies

where you generate pseudo kinship

as a means of generating peace.

One example, traditional Bedouin society, here's what happens.

You have two groups who have been having tensions, who've

been fighting, who have been having some clan warfare,


And they have now figured out a way

to have a treaty to stop fighting with each other.

Here is the ritual that is done, which

is a bunch of the old guys from each of the groups come.

And they sit down.

And they start exploring each other's genealogies.

Who is your great grandparents?

Who is your great, great, great, going through all of that.

And at some point, one of them has the job

of making up an imaginary relationship between the two


Chuck, are you kidding?

I had a great, great grandfather named Chuck also.

We're relatives.

A ritual absolutely transparent that people go through

there to generate a supposed rationale for relatedness,

a big ceremony of pseudo kinship.

Another one is seen in some aboriginal groups in Australia.

Apparently, this is a motif that pops up often

in aboriginal rock art.

And, apparently, it's a symbolic version of this phenomenon.

OK, you've got somebody wandering

through the great back of beyond there.

And there are very few sources of water.

There's a water hole up ahead.

You've just walked 10 miles to come to it.

And you suddenly notice a stranger

coming towards the water hole from the opposite direction.

And this is a water hole that is essential for you to survive.

You are not going to be able to walk far enough to get

to the next water hole.

Maybe what you should do, just in case

this person winds up being aggressive,

is you should attack him first-- a virtual guarantee

of aggression.

Here's a ritual that has been worked out instead

that bypasses it.

The two individuals sit down around the waterhole.

And each starts giving their genealogy.

I am the son of, who's the son of, who's the son of.

Into the next bar mitzvah, whatever.

Oh, we're relatives.

Let's share some water.

They don't fall for it for a second.

But it is a totally artificial mechanism of pseudo kinship

to make it possible for two strangers

to share this absolutely essential for life resource,

and not try to kill each other.

Same sort of thing, pseudo kinship

in all sorts of historical examples, of revolutions.

Revolutions generating pseudo kinship,

what is often the term people use for each other

after the revolution?

Sisters, brothers unite, pseudo kinship terms.

In French, for example, there is in the informal to tense.

And there's the more formal one.

And you're supposed to use the more formal run

sort of in the outside world.

And in the aftermath of the French Revolution,

it became illegal to address somebody, a stranger,

in the formal tense.

It always had to be with the familial

to tense there, pseudo kinship, more and more of it.

So this brings up what is initially

a really, really depressing set of studies, which turn out

to have a very nice optimistic resolution to them--

very disturbing work.

Work done by a number of labs over the years

most notably, Elizabeth Phelps, who is at NYU.

And this is work using functional brain imaging,

amygdala, all of that.

You put people in a brain scanner.

Actually you put one in.

And you put them in one at a time.

And what you do is you're flashing up pictures to them,

flashing up pictures of people, of faces,

of faces at a rapid speed.

So there's virtually no conscious processing.

This is all tapping into subliminal stuff.

And what she reported, and what has been replicated

by a number of other groups since then,

is that you get activation of the amygdala

on the average in people when you subliminally

flash up pictures of somebody of another race.

Whoa, shit, that is distressing to have been found.

That is not a good thing, because this

is totally rapid subliminal stuff, and replicated,

some of the best people in the field showing this.

My God, the amygdala has an us/them

that's, in effect, there in a quarter

second after seeing something.

This is hopeless.

We are so dichotomized.

This is a disaster.

In the years since then, much more interesting stuff

has emerged.

And this has predominately been research

by Susan Fiske at Princeton showing that it doesn't

necessarily work this way.

OK, here's what you do.

First version, you tell somebody,

I'm going to be flashing up pictures

of faces while you're lying there in the brain scanner.

And what you do is you force them

to look at the picture in a way where in a purely

mechanical visual viewing, you're going to say,

some of the pictures have a big red dot

right in the middle of it.

And any time one of those comes up,

I want you to press this button.

In other words, just process the picture

for just a visual pattern.

You do that.

And the amygdala doesn't activate

when you see a picture of somebody of another race.

OK, this is not very exciting.

Now, the next thing she would do--

get people to start thinking categorically.

Here's what you do.

She would now have people going in there saying,

I'm going to give you a bunch of pictures, flashing up pictures.

And what I want you to do is to stop.

I'm going to stop at some of them.

And I want you to look closely.

And tell me, do you think this person is older than age

30 or younger than age 30?

In other words, what you have just requested the person to do

is think of the face in the picture

as belonging to a category, rather than as an individual.

You're going to look at this picture now.

And you don't really need to care who the person is,

or what they look like, or anything.

All you need to do is think of them as part of a category.

And when you bias people like that,

and you flash up the picture of somebody from another race,

the amygdala gets even more activated.

You have primed somebody to think not about individuals,

but to make them think of people in categories.

Finally, what she shows is exactly the opposite.

Now what she does is prime something,

a totally neutral sort of priming,

to try to get people to think of the person in the picture

as an individual.

And she asks totally innocuous, neutral things

along the lines of, I want you to look at the picture.

I know this sounds silly.

But I want you to look at the picture.

And tell me, do you think is this the kind of person who

likes Coke or Pepsi?

Totally sort of diagonal orthogonal

to all of this stuff, get someone doing that.

And now the amygdala doesn't activate.

All you need to do in that study is subliminally prime someone

to think of someone who they're about to look

at as an individual, rather than as part of a category,

than as part of a group.

This is not rebuilding society so that we change our us/thems.

This is a minor prompt 30 seconds before somebody has

the pictures flashed at them.

That's all it took in these studies.

More good news emerged, which was that you would also

see separate of these sorts of manipulations,

long-term developmental aspects that were predictors

of this phenomenon.

People who grew up in racially and ethnically diverse

neighborhoods didn't have this amygdala effect.

People who had had a significant relationship

with a significant other of another race

did not have this amygdala reaction there.

So the easy solution to this being depressing--

OK, early childhood, exposure throughout life, that's great.

That's very good news.

But even more remarkable in her studies is just a prompt.

Prompt somebody to think of that person as an individual.

And your amygdala is not doing an us/them with them anymore.

Now, this whole business about if you grew up

in a diverse neighborhood, that taps into a whole field

called contact theory.

The notion that aggression is decreased,

affiliation is increased, if people have grown up

with lots of contact with people from other cultures,

other societies other religions, all of that,

or if people live in contact with it.

And, in general, what this large literature shows is

it does work that way.

Contact theory, growing up in diverse neighborhoods,

growing up in diverse communities,

increases the likelihood of a broader umbrella

of what counts as an us.

That's good.

Where does it not work?

One realm where most of the studies have shown this

is a realm that's totally heartwarming.

And it would be great if it did work.

But most of the studies show that it doesn't.

These are the circumstances where somebody puts up

the money to take some really poor Irish Catholic kids

in Belfast, and some really poor Irish Protestant kids in there

during the worst of the civil unrest there.

And they get to go to someplace wonderful and far away.

And they all go to summer camp together.

And they have teams that are mixtures of the kids

by different religions.

And they're growing.

They're growing to recognize each other as individuals.

Or the versions, lots of which have been tried,

of sort of retreats or even camps of Palestinian teenagers,

Israeli teenagers.

These are the leaders in the future.

They will go back and have learned they're not

so different after all.

They're kind of just like us.

What those studies have generally shown

is that doesn't work.

It works for only a little while.

You can't just pull it off on a two-week camping trip.

It takes more sustained exposure.

It basically requires growing up in, or living sustainedly in.

So that's been a disappointment.

One additional disappointment with the contact theory

literature, which is one of the papers, which again I think I

put in the suggested reading.

OK, so you've got two different groups,

two different populations, two different ethnicities,


And they are living in generally the same area,

but nonetheless segregated within group in smaller areas.

One scenario-- here's the region where these two groups live.

And there's an absolute boundary between them.

Here, instead, there's sort of an undulating boundary.

It's less clear.

And, critically, there is more surface area.

There is more interfaces between the two groups.

There's more domains of experiencing people

from the other group.

Finally, versions where instead you

have pockets of different groups embedded in other ones.

And that being a completely different scenario

where, in fact, you maximize the perimeter that you get there.

And what's been shown in this one study

that I recommended that you guys look at is the more

contact, the more interfaces, between the two

groups and living situations doesn't guarantee that people

will get along better.

What you will find is there's intermediate points where

the contact profile increases aggression,

because what it does is you just barely

have a critical mass of people on your side

to be an effective group to fight with them.

You see totally different outcomes,

depending on the spatial characteristics

of the subgrouping.

And what the people showed in this paper was

they then analyzed the different ethnic distributions

in the Balkans, the Bosnian War, the Croatians, all of that,

and seeing that this was extremely predictive of where

the violence took place in terms of where you had what they

viewed as the least optimal set of interfaces of contact

between groups.

More contact is not necessarily always equal,

more understanding and we're all just the same.

More contact can equal, in some cases, more irritation,

and more resources, and more unity to do something about it.

OK, more of pseudo kinship-- so this whole notion, again,

of pseudo kinship, we are species

where we're not recognizing individuals

by smell, all of that.

We're doing that cognition stuff.

But don't forget the [? kibbutz ?] study.

But we're doing that cognition stuff.

And, thus, we can do pseudo kinship.

And, thus, we could be manipulated

by powers that be, by governments, by religions,

and to viewing non-relatives as more related to us,

and all of that.

These are very abstract processes.

And it brings up another realm, an extremely abstract realm,

that pushes for more cooperation and less violence.

And this goes back to what I was talking

about the other day, the neurobiology of symbols,

how we code for certain types of symbols,

certain metaphors in our brain.

And that's back to that whole world

of, you're using the same part of the brain

for disgusting food and moral disgust, warm drink,

warm personality, that weird concrete literalness.

Because you've got a pretty metaphors somewhere

when humans started developing them,

the outcome of that being that metaphors

can be extraordinarily powerful.

And a number of researchers-- probably

the person most visible in this realm, an economist

University of Michigan named Robert Axelrod

as doing a whole lot of work showing, in a sense,

the importance of symbols in peacemaking.

And it makes perfect sense.

You take the extreme rationalist view

of humans as economic machines.

And what peacemaking is going to be purely about

is figuring out contested resources

and how they are going to be divided up.

And what Axelrod and others show,

instead, is this whole irrational realm of,

be respectful of somebody else's symbols.

And figuring out how you're going to divide up the land

suddenly becomes a lot less important--

the power of symbols over rational contested resources.

And he studied things like how a critical thing that

happened in peace coming to Northern Ireland

was at one juncture a bunch of the Sinn Fein, however

that's pronounced, the ex-military wing of the IRA

that were just beginning to have extremely

mistrustful negotiations with some of the Protestant unions

and all of that.

They did something outrageous.

They sent a 50th wedding anniversary gift

to this guy Ian Paisley, who was the murderous head

of the Protestant death squads there.

Somebody just decided to try this.

And this was a massive breakthrough.

Anyone who saw that movie Invictus or have read about,

the utter brilliance of Nelson Mandela,

of having spent his time in prison learning

to be completely fluent in Afrikaans

so that when he was sitting down and starting to negotiate

with these people, the fact that he could sit there and speak

in their language, a language that

is so laden with symbolic importance

to Afrikaners, that that was a gigantic symbolic coup

of Mandela embracing the sport that

was the very symbol of apartheid, of Mandela doing

very subtle things that a number of people

pointed out who were involved in the negotiations.

OK, Mandela, just when he's gotten out of prison,

and he's about to meet with some of the leaders

of the government, and some of the most right wing opponents

to any sort of peace.

And so we need a conference room.

And, no, that's not what he did.

He insisted they would have the meetings in his home, his home

that he had just returned to.

OK, well let's clear off the dining room table.

No, that's not what he did.

He would insist they did this in the living room, where

they would sit down on stuffed armchairs and couches.

And something that he did, apparently, always at these

is he would sit down on the couch, and gesture to whoever

was likely to be the most impossible foe,

and say, come sit next to me.

Sit next to me on the couch.

And would proceed to jump up at various points to say,

can I get you some more tea?

Do you want some more-- there would be food.

There would be biscuits.

There would be whatever-- brilliant, brilliant use

of symbols.

If I'm sitting here, and this guy

keeps jumping up and getting me more cookies just when I

was getting a hankering for some more cookies,

maybe not so different after all.

People who get cookies for other people

make the world more peaceful, or something or other.

What Axelrod has also shown in some of his work

is the potential for it-- really interesting stuff.

He will, for example, he and people working with him,

have interviewed, say, Hamas leaders in Palestinian,

and the Gaza, and the West Bank, some of the most

opposed to the existence of Israel, most confrontational

of groups.

And he gets quotes from their leaders along the lines of,

if the Israelis would ever once just say,

we got screwed in 1948.

And we're sorry it happened.

We would be willing to make peace.

And then he goes and talks to some Israeli generals

who are some of the most right wing ones.

He selects them for that.

And they sit there.

And they say stuff like, if the damn Palestinians would ever

just get the anti-Semitic garbage out of their school

books, we'd be able to think seriously about peace

the next day.

It's not about water rights.

It's not about return of land.

It's just about, are they going to respect

our symbols and the legitimacy of our history,

and the accuracy of it?

Enormously, potentially powerful interventions there.

OK, so kin selection-- most importantly, pseudo kinship.

Moving on now-- reciprocal altruism.

Where does that come in, in terms of potentially making

for more peace?

And what's clear is, in principle,

it should never do it if you are playing only a single round

of a game with someone, a game in the prisoner's dilemma

sense, because there's absolutely no reason

to cooperate, because you are never

going to face the person again.

And this is something that was called by a zoologist Garret

Hardin the tragedy of the commons,

and the circumstance of shared resources

but limited responsibility, and limited repeated interactions.

You have to select for selfishness.

You have to select for what is termed a Nash equilibrium,

where the only possible rational thing to do

there is to not cooperate.

So how do you ever get cooperation

to evolve in groups of organisms?

So back to the same Axelrod, his work with computer

tournaments there, with a tit for tat,

seeing that under some circumstances one of them

can dominate.

Tit for tat is a great optimal one.

In the real world, though, how do you ever

jump start cooperation?

How do you ever get one of those strategies going

when the starting state is complete lack of cooperation?

We already know one example, which is founder populations,

that whole business about get an isolated population has

a higher coefficient of relatedness, inbred,

out of kin selection.

Establish high degrees of cooperation.

They come back.

And it's this group selection phenomenon of,

you better become as cooperative as them.

Or you're not going to be able to compete.

And you could see the same exact thing

in circumstances where it is not a founder

effect of a population goes away for a while

and then comes back, but where a population is functioning

in that way amid a sea of non-cooperators.

In New York City in the 1980s, there

was this totally weird phenomenon

in that there were two ethnic groups that

were moving into New York at a much higher rate

than in the past-- Korean immigrants

and Lebanese immigrants.

And both groups happened to gravitate towards grocery

stores-- the Korean community fruit, vegetable stands,

the Lebanese community more regular old grocery stores.

And they were incredibly successful.

And these popped up all over the place.

And the people who already had the fruit and vegetable

stands and stuff started complaining that they

were at an unfair disadvantage.

How come?

Because these Korean shop owners would

cooperate with each other.

They would give each other interest-free loans.

That's not fair.

That's not fair that they're being nice to each other.

We can't compete.

And the same thing with the Lebanese grocery owners,

that you had people doing reciprocal altruism

in a community of trust.

And what they were immediately doing

was out competing the non-cooperators.

And amid these bizarre demands for, like, banning Korean fruit

and vegetable stands, or some-- like,

this was a point of great hostility

during that period in New York City

because those people were cheating.

They cooperated with each other.

So either join in.

Or you will be driven to extinction.

So that is one possibility.

What are the other circumstances in formal game theory

play that favors the emergence of cooperation?

Critical one-- repetition, that you're

going to play against this individual more than just once.

If it's run time, it's tragedy of the commons.

There is absolutely no reason to select for cooperation.

Repeated interactions, and it opens up

the possibility of you being punished

for being a cheater, what they call

the shadow of future retribution.

One qualifier with that, though-- you

need to have multiple rounds of interactions.

But it can't be a known number of rounds.

You can't know how many rounds it's going to be.

Think through this.

You know that this is the very last round

you are going to play.

And what's the only logical thing to do is to cheat?

The very last round functions as if it

was a tragedy of the commons single game, single round game.

So the only logical thing to do is

to cheat in the very last round.

In which case, the only logical thing to do

is to cheat in the next to the last round,

and the next to the last.

A known number of rounds of interactions

immediately does in cooperation because it sort of

flows backwards with this collapse of the system.

The next thing that favors it is what is called open book

play by people in the business, which is you

will be playing against a number of different individuals,

and pairs, cycling through.

And the critical thing is when you

begin to play with someone else, they

can know your record as to how you played in previous games.

In other words, once you bring in reputation,

when reputation can be possible, suddenly you

select for cooperation.

Next, what's shown is that if you have people playing

in multiple games with each other,

especially when they're unsynchronized,

you select for cooperation as well.

What's this about?

What you do is if one of the games makes it very,

very easy in terms of payoff for cooperation

to get established, if you intermix rounds

of that game with a game in which there is very little

motivation for cooperation starting, what you see

is a psychological bleed over.

If you are cooperating with this person in this game, which

is now done here now down here, it greatly

increases the odds of one doing the other game of beginning

to cooperate as well.

Multiple games, and it does not take

much to see that this is more like the real world

than playing prisoner's dilemma with one single individual.

Next, the possibility of punishing someone

when they are a creep.

And that's what we heard about before, what

is termed now in the field altruistic punishment.

If somebody does something crummy to you,

you are allowed to expend a certain amount

of your resources to take more of the resources

away from them.

That selects for cooperation.

Something that even selects faster

is second party altruistic punishing.

You are not taking part in the game.

You're watching these two individuals,

But you have the power to use some of your resources

to punish a cheater-- an outside enforcer.

That selects for cooperation even faster.

Then something that is even more effective, which is

termed secondary altruistic punishing.

Here's what you do.

What you do is people are observers

of other people's interactions, and seeing if they're cheating.

And they can do some altruistic punishment

if they think this individual is a jerk and all of that.

But here's what you do.

If there is a circumstance where somebody cheats

and this third party individual doesn't punish them,

they get punished.

What's that about?

That's honor code violations.

That's the expectation that you are

supposed to report someone who has had an honor code


And if you don't, you will get punished.

That selects for cooperation really fast also.

And all of these-- these have been computer tournaments,

and all of that.

You know that world of research by now.

Finally, more subtle stuff, gives the person

the opportunity to drop out of the game,

to secede from the game.

Give the person the opportunity to not play against you,

but to choose, I'll play against all these other individuals,

but not that one.

Begin to put that power in there.

And you select for cooperation that much faster.

So that's some good news.

Final level, the group selection level-- group selection

not in our behaving for the good of the species,

but as we know the more modern version of it,

selection for traits that are only

manifest at the level of whole groups.

A always loses to B. But groups of A always defeat groups of B.

All of the stuff we've been seeing,

people suddenly cooperating with each other as a small group,

and driving the non-cooperators out of business,

that's a group selection argument going on there.

So you can have that as a means for generating

a lot of cooperation.

That's great.

That makes the world a better place,

unless there is a downside to it.

And back to chimpanzees, what do you

have when a bunch of related chimps

are having not individual fights with males from the next valley

over, but functioning as a group?

You are having an example of group selection, which

thus brings up one of the most profoundly scary things

on this planet, which is when you've

got a bunch of males who are getting

along well with each other.

And they're beginning to look at the neighbors,

because lots of males cooperating together

can make for some very bad neighbors.

As some people in the field have emphasized,

a decrease in homicide within a group

is a prerequisite for inventing genocide between groups.

So group selection is not always this magical founder effect

of everybody wanting to learn the new folk songs.

What you've got instead are circumstances

where it can go very wrong.

Final amazing example showing the emergence

of cooperation-- and this was not

a game theory demonstration.

This was not an experiment.

This was a real event that happened,

and an extraordinary one.

This occurred during World War I. A lot of people

have heard about a phenomenon that happened there,

a historical incident that was very, very cruel,

but pales in comparison to what I'm about to tell about.

In 1914, the first Christmas of World War I, somehow

the decision was made that there was going

to be a truce on Christmas Day.

All of the fighting up and down the trenches

was going to cease for 24 hours.

And it has been documented.

It was amazing and bizarre.

Men out of the trenches playing soccer

with each other from different sides-- a bunch of German

and French guys playing against some British and German guys

on the other side, people exchanging gifts,

people exchanging helmets as souvenirs,

people singing together, people getting drunk together

from the two opposite sides.

And, eventually, when the officers

got them to go back to their job,

they returned to trying to kill each other-- amazing, bizarre


What was very striking about it is it extended,

actually, two or three days extra longer than

planned because the officers couldn't

get people to stop doing this.

That's very cool.

But that's an outside force already establishing

the cooperation.

Here's something much, much more impressive.

And this happened in World War I.

And it didn't take a bunch of generals or heads of states

to negotiate a truce-- the way in which truces

would spontaneously merge over and over again

across the trenches.

How do you generate a reciprocally altruistic

cooperative relationship with the enemy

in the trenches over there, where

you don't speak the same language

and you don't even see their faces?

Here's what you do.

You take your best gunner.

And have him come up and lob a shell

20 yards behind the trench there, and blow up a tree.

Now have you gunner lob a shell to hit the exact same spot

again, and do it again, and do it again.

Do it a bunch of times.

What are you communicating to the other side?

This guy's really good.

And we're choosing not to put the missile down on top of you.

What are you going to do about it?

And then the other side would get out their best gunner

and do the thing in return.

And you have just worked out a non-aggression pact.

And this occurred over and over again

in the trench warfare, documented in letters

by soldiers back home to parents, saying,

hi Mom and Dad.

Things are OK here.

I hope you're worrying less, because we've

worked out something.

Things are a lot better here.

There's a lot less people getting hurt.

Working it out along those lines, working out a tit

for tat vulnerability where you had

to have a forgiving tit for tat, what if somebody

messed up and accidentally dropped

a shell into the trench on the other side?

They got one shot back.

Letters, dear Mom and Dad, things are OK here.

We had an incident the other day.

We had this new gunner who didn't really

understand how things worked.

And I heard he killed four people on their side.

They shot one back.

They took out three of our people.

But everything is OK now.

Tit for tat, complete with a forgiving element--

this happened again, and again, and again,

in the trench warfare.

And the only thing that stopped it from spreading

is the fact that the officers kept

insisting that nobody else was doing this.

And these guys were going to get shot and court marshaled

if they didn't stop this.

And if they had only had cell phones,

if they only had communication, if they only

had a way of knowing up and down the line

that everybody was doing this, they

would have stopped the war-- not with a treaty,

not with generals, not with heads of state,

not with diplomats, but simply a bottom

up way of evolving cooperation.

And they would have stopped the war

if they knew that they weren't the only ones wanting

to do this-- amazing historical incident.

OK, so this gets us to the end of aggression.

As you probably noticed, this has gone on way long.

This is the longest amount of material

we spend on anything in the course.

And each year, it actually gets longer.

And I actually think I know the reason for it.

Three and a half lectures ago, where

did I start off talking about my recent exposure

to human aggression, which was my doing it,

and tripping up that jerk playing soccer.

And everybody was all excited.

Let me tell you about another time,

the most serious time I have ever been

exposed to human aggression.

This took place when I was about 20.

And this was first year that I was

doing research in East Africa.

During that time, the famed notorious dictator Idi Amin

was running Uganda.

And he was a nightmare.

He was just killing people left and right,

destroying the country, as documented, cannibalizing.

Was a nightmare of a dictator.

Around the time, he made a mistake.

This was spring of 1979, which is he invaded Tanzania and took

over some of the land there, thinking

the Tanzanians wouldn't fight back.

And he miscalculated.

The Tanzania army counterattacked, and drove them

out of Uganda, and decided to drive all the way to Kampala,

the capital of Uganda.

And they overthrew Idi Amin.

He fled the country.

And the country was liberated.

They continued through there.

And they opened up a corridor to the Kenyan border.

So it was now a swath all through the southern part

of the country that was controlled by Tanzania.

So the day after the Tanzanians got things

to the Kenyan border, I went into Uganda.

OK, why?

This was amazing.

This was history happening.

You were hearing on the BBC that people were dancing

in the streets in Kampala.

They had been liberated, amazing chance to see history.

This was-- through our college, I

had been spending a lot of time with Quakers,

and wrestling with those issues, and figured

if there is anything that counts as a just war,

this would be it.

What does this seem like?

All these philosophical principles.

This, actually, of course, was not what was going on.

I was a 20-year-