and chases a sub-adult, who bites an adult female,

who slaps a juvenile,

who knocks and infant out of a tree - all in fifteen seconds.

So, in so far as a huge component of stress is

lack of control, lack of predictability, you're sitting there, and you're just

watching the zebra,

and somebody else is having a bad day, and it's your rear end that's going to get slashed:

so tremendously psychologically stressful

for the folks further down on the hierarchy.

One of Robert's early revelations was identifying the link

between stress and hierarchy in baboons.

Some baboon troops are over one hundred strong.

Like us, they have evolved large brains to navigate

the complexities of large societies.

Survival here requires a kind of baboon political savvy,

with the most cunning and aggressive males

gaining top rank – and all the perks.

Females for the choosing, all the food they can eat,

and an endless retinue of willing groomers.

Every male knows where he stands in society:

who can torture him, whom he can torture,

and who in turn the torturee can torture.

It sounds like a terrible thing to confess after thirty years,

but I don't actually like baboons all that much.

There's been individual guys over the years who I absolutely love,

but they are these schemy, backstabbing,

Machiavellian bastards, they are awful to each other.

so they are great for my science, I mean I'm not out here

to commune with them, they are perfect for what I study...

22 years ago, at the age of 30, Sapolsky's landmark research

earned him the McArthur Foundation's Genius Fellowship.

His early work,

measuring stress hormones from extracted blood, led to two remarkable discoveries.

A baboon's rank determined the level of stress hormone in his system.

So if you're a dominant male, you can expect your stress hormones to be low.

And if you're submissive, much higher.

But there was an even more revealing find.

In Sapolsky's sample, low rankers, the "have-nots",

had increased heart rates and higher blood pressure.

This was the first time anyone

had linked stress to the deteriorating health

of a primate in the wild.

Basically, if you're a stressed, unhealthy baboon in a typical troop,

high blood pressure, elevated levels of stress hormones,

you have an immune system that doesn't work as well,

your reproductive system is more vulnerable to being knocked out of whack,

your brain chemistry is one that bears some similarity to what you see

in clinically depressed humans,

and all that stuff, those are not predictors of a hale and hearty old age.

Twenty years ago, Robert got a shocking preview of this idea.

The first troop he ever studied, the baboons he felt closest to

and had written books about, suffered a calamity.

It would have a profound effect on his research.

The Keekorok group is the one I started with thirty years ago.

And they were your basic old baboon troop at the time, which means

males were aggressive and society was highly stratified and

females took a lot of grief - your basic, off-the-rack baboon troop.

And then about by now almost twenty years ago,

something horrific and scientifically very interesting happened to that troop.

The Keekorok troop took to foraging for food in the garbage dump

of a popular tourist lodge.

It was a fatal move.

The thrash included meat tainted with tuberculosis.

The result was that nearly

half the males in the troop died.

Not unreasonably, I got depressed as hell and pretty damn angry about what happened,

you know, when you're thirty years old you can afford to expend a lot of emotion on a baboon troop,

and there was a lot of emotion there.

For Robert, a decade of research appeared to have been lost.

But then he made a curious observation

about who had died and who had survived.

It wasn't random who died. In that troop, if you were aggressive,

and if you were not particularly socially connected,

socially affiliative, you didn't spend your time grooming and hanging out:

if you were that kind of male, you died.

Every alpha male was gone.

The Keekorok group had been transformed.

And what you were left with was twice as many females as males,

and the males who were remaining were, you know, just to use scientific jargon,

they were good guys. They were not aggressive jerks,

they were nice to the females, they were very socially affiliative,

it completely transformed the atmosphere of the troop.

When males baboons reach adolescence,

they typically leave their home troop and roam,

eventually finding a new troop.

And when new adolescent males would join the troop, they'd come in just as jerky

as any adolescent males elsewhere on this planet,

and it would take them about six months to learn:

"We're not like that in this troop. We don't do stuff like that. We're not that aggressive,

we spend more time grooming each other, males are calmer with each other,

you do not dump on a female if you're in a bad mood."

And it takes these new guys about six months,

and they assimilate the style, and you have baboon culture,

and this particular troop has a culture of very low levels of aggression

and high levels of social affiliation, and they're doing that twenty years later.

And so the tragedy had provided Robert with a fundamental lesson,

not just about cells,

but how the absence of stress could impact society.

Do these guys have the same problems with high blood pressure?

Nope. Do these guys have the same problems with brain-chemistry

related to anxiety, stress hormone levels? Not at all.

It's not just your rank, it's what your rank means in society.

So what do baboons teach the average person in there?

Don't bite somebody because you're having a bad day,

don't displace on them in any sort of manner,

social affiliation is a remarkably powerful thing,

and that's said by somebody who lives in a world

where ambition and drive and type-A-ness and all of that sort of thing dominates.

Those things are real important, and one of the greatest forms of sociality

is giving rather than receiving,

and all those things make for a better world.

Another one of the things that baboons teach us is

that if they are able, in one generation, to transform what are supposed to be

textbook social systems sort of engraved in stone,

we don't have an excuse when we say there are certain inevitabilities about human social systems.

And so, the haunting question that endures from Robert's life's work:

are we brave enough to learn from a baboon?

The Keekorok group didn't just survive without stress:

they thrived.

Can we?