Chapter 9: Centuries to Millennia Before

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Okay, let's unpack this.

We often assume our individual abilities, like how good we are at math, are simply biological, right?

Yeah.

Just inherent to who we are.

Yeah, that's common thought.

But what if I told you that something so fundamental could be profoundly shaped by, well, the invisible hand of culture, in ways you might not even realize?

Get this.

In 1983, for every one girl scoring in the highest percentile on the SAT math, there were 11 boys.

11.

Wow.

That sounds like a clear biological difference, doesn't it?

It certainly did to many people for years.

I mean, people linked it to testosterone, all sorts of things.

Right.

But then this groundbreaking paper came out in Science in 2008.

They looked at math scores and gender equality across 40 different countries.

Okay, how did they measure equality?

They used economic, educational, political indices, you know, a broad measure.

And what they found was just astonishing.

The more gender equal the country, the smaller the math score gap between boys and girls.

No kidding.

And in fact, in places like Iceland, really high quality,

girls were actually better at math than boys.

Better.

Not just equal, but better.

Yeah.

So that single finding.

Yeah.

What does that immediately challenge about our, like, basic assumptions?

Well, it just blows up the idea of a fixed biological destiny for things like this.

Yeah.

It makes it crystal clear that what we often see is just innate talent.

It can be deeply molded by the culture we grow up in.

Culture isn't just, you know, the background scenery.

It's an active ingredient.

It shapes our capabilities, even our brains.

And there it is, the aha moment right at the top.

So today we're diving into exactly that, how culture and biology are constantly co -evolving.

Right, this constant feedback loop.

How our environments shape our cultures and then how those cultures reach right back into our brains, influencing our behavior, you know, from our best to our worst.

It's a huge topic.

It is.

And for you listening, you'll discover these systematic patterns of cultural variation.

You'll explore how different brains can produce different cultures and vice versa.

And you'll see the role ecology plays in all of this.

Yeah, the environmental piece is key.

OK, so to start, basics.

What exactly is culture?

There's that classic 19th century definition from Edward Tyler.

Very human centric.

Right.

The complex whole knowledge, belief, art,

morals, law, custom, everything acquired as a member of society.

Very formal.

Pretty comprehensive.

Yeah.

But very much about humans.

Exactly.

And that human exclusive view got a major shakeup back in the 1960s thanks to Jane Goodall.

Ah, the chimpanzees.

You got it.

She reported that chimps make tools, you know, stripping leaves for termite fishing.

Yeah.

Using rocks like anvils to crack nuts.

Right, the anvils, I remember that.

Even sharpening sticks to hunt bush babies.

And maybe even more strikingly, there was this female chimp in Zambia.

She started wearing a blade of grass in her ear, like just because.

A fashion statement.

Pretty much.

A chimp fashionista.

And this trend, this fashion, it actually spread through her group.

So that's cultural transmission,

not genetic.

Precisely.

Non -human cultural transmission.

It totally challenged the old definitions.

So if chimps have it, maybe we need a broader definition.

Frans de Waals seems more practical.

Yeah, I like his.

Culture is simply how we do and think about things.

Transmitted by non -genetic means.

Simple.

Effective.

It covers a lot.

And OK, sure, there are human universals.

Donald Brown listed a ton of them.

Right.

Things like aesthetics, magic, marriage, cooking, names, dance, play, empathy, humor, tools.

The list goes on.

Even toilet training.

Yeah, some things seem baked in.

But for this deep dive, what's really, really captivating are the differences between cultures.

Absolutely.

The universals are interesting, but the variation is just staggering.

I mean, your life expectancy.

93 years in Monaco, 39 in Angola.

That's insane.

Or your chances of being murdered.

Honduras versus Singapore,

450 times more likely.

It's like different planets.

Your entire world is painted by the cultural context you land in.

Couldn't put it better.

So let's talk about one of the biggest divides researchers see.

Collectivism versus individualism.

Ah, yeah, this is a fundamental one.

Collectivist cultures, you often see them in East Asia.

They really prioritize harmony,

interdependence, you know, what's good for the group.

Right, like that classic example of the math question.

And nobody answers even if they know it, because they don't want to shame the classmates who don't.

Exactly.

The group harmony trumps individual display.

Whereas individualist cultures, like say America, put a premium on autonomy, personal achievement, individual rights, looking out for number one.

And it shows up everywhere.

Yeah.

Individualists tend to define themselves personally.

I'm a graphic designer.

I'm smart.

They use the word I a lot more.

Okay.

And they attribute success to their own internal traits.

I succeeded because I'm good at this.

Makes sense.

If you ask them to draw a sociogram, like a map of their social world, they usually put themselves right in the middle big circle.

And collectivists.

Flipped.

They define themselves more relationally.

I'm a parent.

I'm part of this team.

Success is often seen as situational.

The team did well.

I got lucky.

And the sociogram.

Their self circle is often smaller and further from the center embedded within the group connections.

That's a really clear visual difference.

But okay, here's the kicker.

Does this stuff actually get under the skin?

Like into our biology?

Are there neural correlates?

Oh, absolutely.

This is where it gets really fascinating.

These cultural differences, they're mirrored in brain activity.

Like how?

Okay, take the medial prefrontal cortex, the MPFC.

It's involved in thinking about yourself, emotional processing related to self.

Individualists show strong MPFC activation when they look at pictures of themselves.

Much less when looking at pictures of say, their mom or best friend.

Okay.

East Asians.

Much less difference in activation between self and close others.

It's like the self other boundary is neurologically less distinct.

Wow.

Okay, what else?

Stress responses.

Ask Americans to recall times they influenced others.

They do it easily.

Ask East Asians to recall being influenced and these easily.

Force them to do the opposite.

Let me guess stress.

Bingo.

Both groups start secreting glucocorticoids, those stress hormones.

It's literally stressful to act against your cultural grain.

That's wild.

Even dopamine.

Even dopamine are reward systems.

European Americans tend to get a dopamine hit from excited facial expressions.

Chinese subjects in one study got a more from calm expressions.

Different things feel rewarding.

So these aren't just like surface preferences.

They're wired in deep.

And you mentioned cognitive processing differences too.

Richard Nisbet's work.

Exactly.

Huge body work there.

Broadly, Westerners tend towards more linear, analytical, object -focused thinking.

East Asians lean towards more holistic, relational, context -focused thinking.

I mean, an example.

Okay, explain why a ball is moving.

A typical Western answer might focus on the ball itself, its weight, its momentum.

An East Asian answer is more likely to include environmental factors, friction, the slope it's on, context, interactions, or the classic test.

Monkey, bear, banana,

which two go together.

Monkey and bear.

They're both animals.

Categories.

That's the typical Western answer, categorical grouping.

The common East Asian answer,

monkey and banana.

Relational.

A monkey eats bananas.

Exactly.

Relationship over category.

And this extends to just basic perception.

Show people a picture, say, a person standing in a busy street scene.

Okay.

Ask them later what they remember.

Westerners are much more likely to remember details about the main person.

East Asians remember more about the background, the context.

Their eyes actually move differently.

Right, they do.

Eye tracking studies show Westerners tend to fixate on the central object or person.

East Asians tend to scan the whole scene more, taking in the relationships between elements.

And forcing them to switch styles.

Makes the cortex work harder.

It takes effort to override your culturally ingrained processing style.

This is blowing my mind a bit.

So where do these profound differences come from?

You mentioned ecology earlier.

Right.

The argument in the chapter links it strongly to the environment and historical ways of life.

So for America's individualism.

It's often tied to a history of immigration.

People who chose to leave were maybe already more restless, unconventional.

Plus, the moving frontier, always rewarding novelty and self -reliance.

Makes sense.

And East Asia's collectivism.

The big link here is rice cultivation.

Growing paddy rice for millennia required massive coordinated communal effort.

How so?

Think about it.

You need to terrace mountainsides, build complex irrigation systems, manage water distribution fairly among neighbors.

You absolutely cannot do that alone.

It forces cooperation, interdependence.

For generation after generation, Sapolsky uses a great line.

The roots of collectivism, like those of rice, run deep in East Asia.

That's powerful.

Are there exceptions that prove the rule?

There are.

Really cool studies.

One look within China.

Northern China traditionally grew wheat requires much less cooperative labor than rice.

And guess what?

People in those northern wheat growing regions, they show more individualistic traits, higher divorce rates, more patents filed closer to western patterns than southern rice growing Chinese.

Wow.

Within the same country.

Yeah.

And another study in Turkey looked at communities near the Black Sea.

Some were farmers or fishermen, cooperative work.

Others were herders, more solitary.

And the herders.

Showed more individualist cognitive patterns.

Better at judging absolute lengths, more categorical grouping, just like westerners.

While the farmers and fishermen showed more collectivist patterns, ecology shapes culture.

It's incredible.

And as coevolution goes down to the genetic level, too, you mentioned.

Yeah, briefly.

There's this gene variant, DRD47R, linked to novelty -seeking restlessness.

It's way more common in populations with long migration histories.

And in East Asia?

It's almost absent.

The theory is that in settled collectivist rice farming societies, selection actively worked against that restless, novelty -seeking gene.

Conformity was more adaptive.

Biology and culture shaping each other.

Okay, shifting gears a bit, but still on deep cultural patterns.

Cultures of honor.

Where do these come from?

These are really strongly linked to nomadic pastoralism.

Herding cultures.

So think deserts, grasslands.

Exactly.

Environments where agriculture is tough, it's wide open, and there's often minimal state control, minimal police force.

And the key vulnerability.

Your wealth is portable.

Thieves can steal your herd.

You can't easily steal acres of farmland, but you can drive off someone's sheep or camels overnight.

Right.

Big difference.

And that environment fosters a specific cultural package.

You often see more militarism, warrior classes, maybe an emphasis on a glorious afterlife for warriors.

Even things like economic polygyny, authoritarian parenting styles.

And religion.

Often monotheistic.

The thinking is that these harsh, singular environments, big sky, stark desert,

lend themselves to the idea of a single, powerful,

interventionist god.

Unlike, say, rainforests teeming with life, which tend towards polytheism.

Interesting.

But the core is the honor part.

Absolutely.

Cultures of honor have strict rules about civility and hospitality, often vital for survival in tough environments.

But the defining feature is the need for swift,

decisive, often violent retribution for insults or challenges.

To your reputation, your family, your clan.

Why so strong on retribution?

The logic is brutally practical.

As Sapolsky puts it, if they take your camel today and you do nothing, tomorrow they will take the rest of your herd, plus your wives and daughters.

You have to project an image of someone not to be messed with.

Deterrence is everything.

And we see echoes of this in, say, the American South, historically.

Definitely.

The traditional South had strong elements of a culture of honor, the emphasis on hospitality, chivalry, family legacy, reputation.

You mention Andrew Jackson.

Right.

His mother telling him, essentially, don't rely on the law, handle insults yourself.

And he did, with duels and brawls.

Where formal law is weak, personal justice often fills the void.

Common law and lynch law could seem ethically compatible in that mindset.

And this leads to a specific kind of violence, right?

Not just general mayhem.

Exactly.

It's disproportionately rural, often happens between acquaintances, and it's triggered by perceived slights to honor.

Someone disrespects you, flirts with your spouse at a reunion, challenges your word.

And Southern juries, historically, were often lenient in these cases.

There's that famous study, The Asshole Experiment.

Newspitt and Cohen's classic, yeah.

Brilliant setup.

They took male college students, Southerners and Northerners, got baseline hormone levels.

Okay.

Then the student walks down a narrow hallway to drop off a questionnaire.

On the way back, a confederate bumps into him, slams a file drawer, and mutters, Asshole.

Subtle.

Right.

Then they measure hormones again and give him a scenario completion task, like how a story involving an insult might end.

And their results.

Huge difference.

The northerners mostly shrugged it off.

Maybe amused, maybe annoyed, but hormones didn't change much.

Violent scenarios didn't escalate.

But the southerners?

Massive spike in testosterone and stress hormones, the glucocorticoids.

And in the follow -up scenario, a huge jump in imagining violent conclusions.

The insult landed differently biologically and psychologically.

Wow.

That cultural programming runs deep.

But this honor imperative, it can also turn inward, right?

Towards horrific violence, like honor killings.

Tragically, yes.

This is the darkest side, where a family feels its reputation has been so badly tarnished, usually by a female relative, that they feel compelled to kill her, or sometimes the perceived despoiler, to restore the family's face or honor.

It's hard to even comprehend.

What kind of crimes are we talking about?

It's devastating.

Refusing an arranged marriage, seeking divorce, sometimes just wanting education, dressing in a way deemed too Western, interacting with unapproved males, infidelity, converting religion.

Or even being the victim of rape.

Or even being raped.

It's seen as bringing shame, regardless of fault.

And men can be victims too, often for homosexuality.

How is this different from, say, typical domestic violence?

Several key ways.

It's often committed by male blood relatives, brothers, fathers, uncles, sometimes with the approval or complicity of female relatives.

It's usually planned, not a spontaneous act of passion.

It's often rationalized on cultural or even religious grounds, with little remorse shown.

And crucially, it's often done openly to make a public statement, sometimes even using underage relatives to carry it out to get lighter sentences.

That's chilling.

The scale.

UN estimates are 5 ,000 to 20 ,000 victims a year.

Somewhere in that horrifying range.

It's a global tragedy rooted in these deeply ingrained cultural codes about honor and shame.

Okay.

Let's shift from honor to another major shaper.

Inequality.

How resources are distributed.

Right.

We can think about cultures as being on a spectrum from highly stratified, big differences in wealth and status to more egalitarian.

Hunter gatherers were mostly egalitarian?

Generally, yes.

Because there wasn't much stuff to accumulate.

Inequality really took off with agriculture and animal domestication.

Suddenly you had surplus food, land, animals, things to possess, things to inherit.

So why did stratified, unequal societies tend to dominate historically?

Well, Peter Turchin argues they were simply better conquerors.

They had chains of command, specialized roles.

They could organize for warfare more effectively than egalitarian bands.

The military advantage.

And also maybe a survival advantage in unstable environments.

Stratified societies could essentially sequester mortality in the lower classes.

When famine or disease hit, the poor suffered and died disproportionately, allowing the overall structure and the elites to survive.

This is a grim calculation.

But this inequality, it comes at a huge cost, right?

Affecting everything from basic kindness to health.

Huge costs.

Let's talk about social capital.

This isn't economic capital like money.

It's the trust, the reciprocity, the participation in community groups, the glue that holds a society together.

Okay.

And there's a strong inverse relationship.

Cultures with more income inequality tend to have less social capital.

Why is that?

Because hierarchy,

which inequality breeds, is fundamentally about power and domination, not reciprocity and trust.

If resources are unequal, power is often unequal too.

People trust each other less, cooperate less.

And we see this in experiments.

Yeah.

In more unequal societies, people in experiments are less helpful, less cooperative.

You see more bullying.

You even see that weird antisocial punishment, where people will actually punish someone who's being too generous, more harshly than they'll punish someone who's cheating.

Seriously, punish generosity.

It disrupts the established hierarchy, perhaps.

And the powerful in unequal systems tend to create and believe myths about why the system is fair, you know, the hidden blessings of subordination.

Yeah.

Justifying the status quo.

And this seeps into health and crime too.

The seashells gradient is famous.

Absolutely.

Lower socioeconomic status evals worse health, more disease, shorter life.

It's one of the most robust findings in public health.

And it's not just about being poor, is it?

No.

That's the critical insight from researchers like Nancy Adler and Richard Wilkinson.

It's not just being poor in absolute terms, but feeling poor, your subjective SES, and what makes people feel poor.

Seeing others with much more.

Exactly.

Poverty amid plenty.

Income inequality.

It constantly reminds you of your lower status breeds chronic stress.

And this stress, it has biological pathways.

Two main ones propose the psychosocial pathway.

Less social capital, more stress from lack of control, lack of predictability, lack of social support.

This leads to chronic activation of the stress response system, which literally corrodes your health over time.

Okay.

And the other?

The neomaterialist pathway.

This argues that in unequal societies, the wealthy effectively secede from public services.

They use private schools, private security, gated communities, bottled water.

They benefit less from and therefore invest less in public goods like education, healthcare, infrastructure.

Which leads to private affluence and public squalor.

Precisely.

Yeah.

And that public squalor harms everyone else's health.

And for crime and violence, it's a similar story.

Again, it's not absolute poverty, but poverty amid plenty inequality that's the stronger predictor.

Staining pathways.

Pretty much.

Neomaterialist,

less investment in things like education, which is a key crime fighting tool.

Psychosocial, the stress, the frustration, the lack of opportunity.

Plus, displaced aggression.

The ending.

When inequality fuels violence, it's mostly the poor preying on the poor.

Not the poor rising up against the rich.

Like that air rage analogy you used earlier.

Exactly.

Having a first class section quadruples coach rage.

Making coach passengers walk through first class doubles it again.

But who do they yell at?

Fellow coach passengers, flight attendants.

Not the people in first class.

The aggression gets displaced downwards or sideways.

Fascinating.

Okay, beyond resources, what about just how we live together?

Population size, density, diversity.

Huge factors.

Urbanization is the big one.

Since 2008, most humans live in cities.

And cities bring benefits generally healthier, wealthier, more innovation.

But also downsides.

Effects on the brain.

Yeah, some studies suggest the larger the population someone grew up in, the more reactive their amygdala the fear stress center is during social stress tests later.

And the anonymity.

Big one.

City living means constant encounters with strangers you'll likely never see again.

This fosters anonymous interactions, both good and bad.

Crime fiction basically arose with cities.

Because in a small village, there's no who do it, everyone knows everyone else's business.

Right.

So how do cities handle norm enforcement without everyone knowing everyone?

They develop new mechanisms.

Harsher punishment for violations, maybe.

More emphasis on abstract rules for treating strangers fairly.

And critically, third -party punishment.

Meaning police, courts.

Exactly.

Instead of direct revenge, you have the state, the people versus joblo, enforcing norms.

And relatedly, Erinner and Zion argues, this is where big gods come in.

Big gods.

Moralizing, punishing deities concerned with how humans treat each other, especially strangers.

These tend to emerge only in societies large enough for anonymous interactions, where reputation alone isn't enough to enforce cooperation.

Belief in such gods predicts greater generosity, specifically towards strangers who share the same religion.

Okay, what about density?

Just being packed together.

Does that make us crazy?

Like those old rat studies suggested?

Ah, Calhoun's rat slums.

His 1950s experiments were widely interpreted or misinterpreted as showing high density inevitably causes aggression, social breakdown, the behavioral sink.

But that wasn't quite right.

Not really.

A closer look showed density didn't make all rats aggressive.

It made the already aggressive rats more aggressive, and the timid rats more withdrawn and passive.

It basically exaggerated existing social tendencies.

So it amplifies, doesn't necessarily create.

Exactly.

And look at humans.

Some of the densest places on earth, Hong Kong, Singapore, Tokyo, have very low rates of violence.

High density clearly doesn't automatically equal pathology.

It interacts with culture.

High density does predict cultural tightness, though.

Tightness?

Yeah, cultures with stricter norms, more monitoring of behavior, less tolerance for deviance, often more autocratic rule,

higher population density, historically and now, correlates with cultural tightness.

Okay, density, size.

What about diversity?

Heterogeneity.

This is complex.

You get both narratives right.

Mr.

Rogers' neighborhood, everyone getting along, world peas.

And West Side Story, sharks versus jets, friction and turf wars.

Exactly.

Both can happen.

The key seems to be the spatial qualities of the diversity, how groups are arranged geographically.

How so?

There was this fascinating study using computer simulations by the New England Complex Systems Institute.

They modeled ethnic mixing.

That conflict wasn't highest when groups were totally separate or totally mixed.

It peaked at an intermediate level of mixing, creating what they called ethnic patches, or surrounded enclaves, pockets of one group surrounded by another.

That spatial arrangement maximized friction.

Did this predict anything in the real world?

Amazingly, yes.

They used this model,

based purely on the geographic distribution of ethnic groups in the former Yugoslavia before the war, to predict where the worst fighting and massacres would occur in the 1990s.

And it worked.

With frightening accuracy.

Their conclusion was that violence can arise due to the structure of boundaries between groups, rather than as a result of inherent conflicts between the groups themselves.

Clear boundaries, mountains, rivers sometimes make for better neighbors than messy patchy borders.

That's sobering.

Okay, final piece of the environment puzzle.

Historical crises.

How do they leave a mark?

Big time.

Acute crises like the London Blitz during WWII or maybe 9 -11 often cause people to pull together, increase solidarity, at least temporarily.

But chronic, ongoing threats.

They have different effects, often leading to more tightness and suspicion.

Think historical food shortages linked to cultural tightness.

Environmental degradation, less farmland, less clean water, is linked to conflict, like Jared Diamond showed in Collapse.

Disease too.

Huge one.

A history of high infectious disease prevalence in a region strongly predicts more xenophobia wariness of outsiders who might carry disease, and more cultural tightness, more conformity.

Makes a grim kind of sense.

What about weather?

Also predictive.

More historical floods, droughts, cyclones.

Also predicts tightness.

And El Nino events, the warming and drying patterns have been shown to double the likelihood of civil conflict erupting in developing countries.

Not by causing the conflict, but by stoking the fires of pre -existing conflicts.

Stressing resources, fraying nerves.

And looking forward, climate change.

The projections are worrying.

Studies suggest global warming could increase rates of interpersonal and group violence by 16 to 50 % by 2050.

Partly resource stress, but also just.

Heat makes people more irritable, more aggressive.

High temperatures reliably rile people up.

Wow.

Okay, one last cultural factor before we get to the big history debate.

Religion.

Right.

A massive cultural force.

Why humans invent religions is a whole deep dive in itself could be about fostering in -group cooperation, our tendency to personify things, a byproduct of our complex social brains.

Lots of theories,

but lots of variety too.

Huge variety.

But patterns emerge, often linked to ecology again.

Desert cultures.

Tend towards monotheism.

Rainforests.

Polytheism.

Pastoralist gods often value war and valor.

Agricultural gods might control the weather.

And those big gods we mentioned, the moralizing ones, tend to show up in large complex societies.

So religion isn't monolithic.

Not at all.

It generally reflects and transmits the values of the culture that invented it.

And because of that, it can be used to justify and motivate both the very best and the very worst of human behaviors.

Okay, so we've seen how culture, ecology, inequality, demographics,

how they shape us now.

But what about our deep past?

How did we get here?

This brings us to that ancient debate.

Hobbes versus Rousseau.

The big one.

Are humans inherently warlike, living lives that were nasty, brutish, and short before civilization tamed us, as Hobbes thought?

Or are we naturally peaceful, corrupted by society, as Rousseau argued?

The noble savage idea.

For centuries, it was philosophy.

Now we have actual data, especially from archaeology.

And what does it say?

Who leans towards Hobbes?

Scholars like Lawrence Keeley and Steven Pinker argue forcefully for the Hobbesian view.

In books like War Before Civilization and The Better Angels of Our Nature, they point to archaeological evidence, they say, shows widespread lethal warfare long before states existed.

What kind of evidence?

Vast graves.

Skeletons with healed fractures.

Or worse, with spear points or arrowheads embedded in them.

Remains showing scalping or cannibalism.

Defensive structures like palisades around ancient settlements.

A specific example.

Jebel Sahaba in Sudan, maybe 12, 14 ,000 years old.

59 skeletons, nearly half showed signs of violence, projectiles.

Crow Creek in South Dakota, 700 years old.

Over 400 skeletons.

Massive evidence of a massacre.

Etsy the Iceman, 5 ,000 years old, died with an arrowhead in his back.

Keeley and Pinker argue that earlier archaeologists kind of romanticized the past, pacified it.

Because they wanted to believe in peaceful origins after WWII.

Okay, sounds compelling.

Is there a counterargument?

The Rousseau side?

Oh yeah.

Strong criticisms come from anthropologists like R.

Brian Ferguson.

He argues Keeley and Pinker are misinterpreting evidence and cherry picking the most violent sites.

Ferguson points out that many sites just show isolated homicides, not necessarily war.

Those arrowheads might be butchering tools or just debris found near bones.

Healed fractures could easily come from accidents or ritualized fighting, not lethal combat.

Cannibalism is really hard to prove conclusively from bones alone.

And the cherry picking charge?

He argues that if you look at all known prehistoric remains globally, the percentage showing clear signs of violent death is actually quite low.

Keeley and Pinker focus on the most extreme cases.

Ferguson basically says absence of proof isn't proof of absence.

But you can't build a case for universal prehistoric war on a few dramatic sites.

Okay, so the bones are debated.

What about looking at contemporary traditional non -state societies?

Hunter gatherers or horticulturalists studied more recently.

Keeley and Pinker use this too.

They point to groups famous for violence, hud hunters in New Guinea, the Yanomamo in the Amazon studied by Napoleon Chagnon.

Chagnon even claimed that Yanomamo men who killed had more wives and children.

More reproductive success for killers.

That sounds pretty Habesian.

It does.

But again, strong criticisms.

Critics like Douglas Fry argue Pinker cherry picks the most violent societies, mostly from the Amazon and New Guinea, ignoring many less violent groups elsewhere.

And the Yanomamo data?

Flawed, according to Fry and others.

Chagnon didn't properly control for age.

Older men naturally have more kids and maybe were more likely to have killed someone and survived.

He only counted surviving killers.

And a link between killing and reproductive success didn't hold up in many other cultures studied.

Plus, are these groups really pure analogs for the past?

Big question.

Many have been massively impacted by the outside world.

They have modern weapons, sometimes traded by the anthropologists themselves.

Their lands are encroached upon.

They're displaced, facing diseases.

They aren't pristine Stone Age relics.

And there's a difference between types of hunter -gatherers.

Crucial distinction.

Many groups cited as violent are what anthropologists call complex hunter -gatherers.

They're often sedentary, living in larger groups, defending rich, localized resources like fishing sites.

They're kind of a transitional form.

Pure, nomadic hunter -gatherers constantly moving in small bands are different.

That Nataruk massacre site likely involved sedentary HG's fighting over prime territory near Lake Turkana.

So to understand our deepest past, we need to look at pure nomadic hunter -gatherers.

What's the record there?

Archaeologically, it's sparse.

Very few cave paintings depict group violence.

Only one potential massacre site truly fits the nomadic HG profile.

What about analogies to other primates, like Wrangham's demonic males idea based on chimps?

Wrangham argues chimp males engage in lethal raiding, suggesting our common ancestor, and thus we have deep roots of intergroup violence.

Criticisms again.

We aren't descended from chimps.

We share a common ancestor.

Bonobos are equally close relatives, and they are famously much less violent.

More make -love -not war.

Wrangham was accused of cherry -picking the violent ape.

Gorillas, for example, show very low rates of lethal aggression.

So the best insights probably come from studying actual contemporary nomadic hunter -gatherers, the few remaining groups.

That seems to be the consensus, and what we find there is fascinating.

First, forget the man -the -hunter stereotype.

Women's foraging often provides the majority of calories.

And they weren't living nasty, brutish lives.

They likely worked fewer hours, ate a more varied diet, and were healthier than early farmers.

Marshall Solons called it the original affluent society.

But were they peaceful?

Rousseau's noble savages?

Initially, some anthropologists thought so, like with the Kung San, called the harmless people.

But longer -term studies, like Carol Ember's work, revealed that lethal violence does happen even in these societies.

It wasn't absent.

So neither extreme is quite right.

That seems to be the nuanced view emerging from researchers like Frye, Soderbergh, and Christopher Bohm.

Here's the breakdown.

Warfare, meaning organized conflict between groups resulting in multiple casualties, actually rare among pure nomadic HG's, only found in a minority of the 21 groups systematically studied.

So not constant war, but violence?

Lethal violence, like homicide.

Yes, that seems common.

Found in something like 86 % of studied cultures.

But it's typically individual disputes, not group battles.

What are the causes?

Mostly mundane, sadly familiar things.

Men fighting over women, disputes over kidnapping women, revenge for a previous killing, spousal killing over adultery,

infanticide, accusations of witchcraft, stealing.

So personal conflicts, not political conquest.

What norms did these groups value?

Despite the violence, they strongly valued fairness, sharing, and preventing anyone from becoming too dominant or bossy avoiding despotism.

How did they maintain fairness, like with hunting?

Cooperative hunting was common, but the successful hunter often didn't distribute the meat.

A third party would, to prevent the best hunter from gaining too much status or power from controlling the food.

Sharing was crucial.

Indirect reciprocity was key.

Indirect reciprocity.

Yeah, A helps B, B helps C, C helps A later.

You build up social credit.

As Sapolsky says, an HG's best investment against future hunger is to put meat in other people's stomachs now.

And preventing bullies, how did they manage that?

Constant vigilance.

And a key tool studied brilliantly by Polly Weisner is gossip.

Gossip, seriously?

Absolutely, not just idle chat.

It was a crucial way to monitor behavior, discuss norm violations, especially by potential bullies or high -status individuals trying to grab power, build consensus, and decide on collective action.

It's social grooming and norm enforcement rolled into one.

What other enforcement methods?

Criticism, public shaming, ostracism, shunning, trying to bring deviance back into line non -violently first.

And if that failed?

Oh.

For serious stuff.

Then, as a last resort, judicial killing, collective execution of a persistent, dangerous norm violator, someone who repeatedly murdered, tried to take over, practiced harmful sorcery, stole constantly, refused to share, betrayed the group.

It's documented in nearly half of pure HG societies.

But it was a group decision, not individual revenge.

So, back to the big question.

Hobbes or Rousseau?

Where does the chapter land?

It lands in a nuanced middle ground.

Nomadic HGs were probably no angels.

They were capable of lethal violence, of murder.

But war organized group conflict.

That seems to have been rare until humans gave up the nomadic lifestyle.

So, the idea that our entire history as a species is just drenched in constant warfare.

Seems unlikely based on the nomadic HG evidence.

Our deep history wasn't constantly soaked in escalated group conflict.

Then what changed?

When did war really take off?

The chapter points strongly towards agriculture as, paradoxically,

a human blunder in this respect.

Oh, so?

Agriculture brought dependence on staple crops,

vulnerability to famine, worse hygiene in settlements, and crucially, surplus.

Ah, stuff to fight over.

Exactly.

Surplus food that could be stored, controlled, and inevitably unequally distributed.

This generated socioeconomic status differences far beyond anything other primates managed with their hierarchies.

And that inequality fueled conflict.

It created the motive, resources to seal, and the means,

larger populations, potential for specialization like soldiers.

Sapolsky concludes, it wasn't until humans began the massive transformation of life that came from domesticating plants and animals that it became possible to let loose the dogs of war.

Wow.

Okay, quite a journey through culture, ecology, and conflict.

Let's try to wrap up the main takeaways.

It's a lot to digest.

For sure.

But today, you've really seen this intricate dance of coevolution, haven't you?

How our brains shape cultures, but then those cultures turn right around and shape our brains.

Especially, it seems, through that flexible frontal cortex during childhood?

Right, the brain is incredibly plastic, especially early on,

and culture provides a lot of the input that shapes its wiring.

And we've uncovered how culture influences us in ways we might expect,

like, it's okay to fight or even kill, depending on honor codes or group boundaries, but also in really surprising ways, like where your eyes automatically look in a picture, or whether you group a monkey with a bear or a banana.

These things feel so basic, but culture sculpts them.

Yeah, it permeates our cognition much more deeply than we usually think.

And we saw how ecology, whether it's rice paddies or deserts or population density, exerts this profound, often paradoxical influence, creating cultural patterns that can last for centuries, even when people move to new environments.

And we waded into that deep ongoing debate about our species capacity for violence.

Were we born warriors, or did settled life, inequality, and agriculture unleash something?

The evidence suggests a more complex story than either Hobbes or Rousseau imagined.

Definitely complex.

Nomadic life wasn't perfectly peaceful, but large -scale war seems like a more recent post -agricultural development, which actually leads to a really fascinating question.

If our past wasn't as bloody as Hobbes thought, but agriculture and states did unleash war and inequality,

why is it that, arguably, humans seem to have gotten significantly less awful to one another on average over the last 500 years or so?

That's the puzzle Pinker tackles later, but this cultural deep dive sets the stage for it.

That was a provocative thought to leave people with, how things have changed more recently.

Okay, well, that's all we have time for on this deep dive.

A huge thank you from the deep dive team for joining us as we explored these powerful, often invisible forces that shape who we are.

Hope you found it useful.

We hope you definitely found some aha moments in there.

Maybe a lot to ponder about your own cultural context.

Until next time, keep learning.