Transcriber: Christina Davis Reviewer: David DeRuwe
Thank you.
Is this working? Yeah.
And welcome to Emory for those who are not from here.
I will be talking about primates and economics,
even though most of the time, I don't think people connect those two,
but I will be doing that.
And I will be challenging the idea of Homo economicus,
which is defined in reaction to Stuart Mill
as someone who desires to possess wealth and knows how to get wealth,
and that's all that you need to get an economy going.
Basically that's the view of Homo economicus.
And of course it was popularized nicely by Gordon Gekko in the movie "Wall Street"
where he says that "Greed is all you need."
And actually, connecting it to the evolutionary spirit ...
greed captures the essence of the evolutionary spirit.
Now, I'm a biologist,
and I know something about the evolutionary spirit,
and I can tell you,
there's much more to it than just greed.
That as a basis is a very narrow basis.
So I will be going sort of from general to more specifics in terms of economics.
If the victory, if getting the resources is all that matters in life,
which is basically what the view is,
then you could not explain
why so many animals have systems where they reconcile after fights,
they cooperate,
they do all sorts of things where they are even generous to others.
And so a lot of behavior in primates cannot be explained that way.
So for example, this is an actual reconciliation.
These are two male chimpanzees who have been in a fight.
And one of them holds out his hand and begs the other for a contact,
and about a second after I took this picture,
the males came together, and they kissed and embraced each other.
Now that's not something that fits that original view
of contest-competition, basically, that people had.
This is a video of it.
This is a female who approaches the alpha female.
She had a big fight with her.
This is the alpha female.
And she kisses her, sort of, and then they groom.
You see the reunion is actually a bit assertive -
like come here -
and that's typical for many reunions in chimpanzees.
There's an assertive element to it.
This is how bonobos do it.
(Laughter)
Bonobos do everything with sex, so why not reconciliation?
And so all the primates
and not just the primates -
there's like 25 primate species in which we have found reconciliation -
but it has been found in goats, in hyenas, in dolphins and elephants.
And basically,
the fact that, after contest, animals come together in a sort of friendly fashion
doesn't fit the view that everything
is about contest and about getting the resources.
The way this operates is that you can have winners and you can have losers,
and of course it's better to be the winner than the loser.
But a zero-sum game is really only something that you find
in between, let's say, territorial fish or territorial birds:
"I chase you out of my territory, which is a good thing,
and then after that, I don't have anything to do with you."
But as soon as you live in a social group, it's very different, actually.
And so, many animals may form friendships like these elephants.
They cooperate, they help each other when there's danger, they support each other,
they warn each other for things, they find food together.
So many animals have these relationships that are highly cooperative.
And they create a very different image.
Basically what you get is you have winners and you have losers,
but there is an area where both of them lose.
So if I have a buddy with whom I do a lot of cooperation,
and I kill him, well, I've lost the relationship.
And if I harm him or injure him that's also not good.
So there is this overlapping area,
which is what we define as the value of the relationship.
And it's because of the value of relationships
that you have reconciliations going on and conflict resolution going on.
And as I said, it's actually found all over the animal kingdom;
it's not just found in the primates.
So we do experiments on teamwork in primates,
and one of the basic questions that we look at is:
"Do they understand that they need the partner?"
Basically, is there an understanding of need, which underlies the cooperation.
I'm going to show you a very old little movie from the Yerkes primates,
and it's now almost a century old; it was made in the 1920s.
And what it shows is chimpanzees cooperating.
This by itself is not so remarkable.
They're highly synchronized, as you see.
They're pulling a heavy box that is too heavy for one of them.
And there's of course food on the box,
otherwise they wouldn't be pulling like this.
(Laughter)
So that's where greed comes in, actually.
So now they bring it in, and it gets more interesting after this.
So these are experiments that were done by Robert Yerkes, long ago,
and at the moment, there's an increased interest in these kinds of things.
So now it gets more interesting.
What they do is they feed one of the two chimpanzees.
So one of the two is not interested in the task anymore.
(Laughter)
So now look at what happens at the very end.
This one basically takes everything.
So there are two interesting elements about it.
This chimp on the right has a full understanding that he needs a partner -
he activates the partner.
And the chimp on the left is willing to work
even though he's not interested in the food.
So there was much more going on here than the food incentive.
There's something else going on, which is the relationship,
which is probably reciprocity between these two juvenile chimpanzees.
And reciprocity is a very big topic in cooperation.
So we recently set up this experiment with elephants.
This was done with Dr. Josh Plotnik, who is here shown.
Just a year ago, he graduated here at school.
We set this up with elephants and the funny thing is,
apart from elephants being very dangerous,
is that you cannot design an apparatus
that is too heavy for one elephant, let alone two elephants.
And so to set up this experiment we had to do something totally different.
What we did is we had a rope around an apparatus -
a single rope -
and so if you pull on this side of the rope,
the rope disappears here,
meaning that two elephants need to grab it at the same time,
otherwise the rope disappears, and you cannot do anything.
So it's a very smart apparatus, and I'm going to show you the first clip,
which is elephants doing this.
It's very hard to do these experiments, so Josh worked in Thailand on this.
Here you see a rope -
a rope here and a rope here -
and you should see two elephants who have been released at the same time.
They're going to walk up to these ropes and pick them up at the same time,
which by itself is not really so challenging for elephants.
So they pick up the rope.
Since they arrive at the same time,
the question of who is going to do what is not particularly relevant to them.
And so now they're eating the food.
So we're going to make it more difficult to see what they understand of this.
And the way to make it more difficult
is to release them with a delay between them.
Elephants are very patient animals, so we went up to delays of 45 seconds.
Here you have an elephant who arrives.
And this elephant needs to be smart enough to wait for the other,
because if he grabs the rope and pulls it, it disappears.
This elephant had his own technique,
which was an illegal technique that we didn't approve of.
(Laughter)
What he did is he would put his big foot on the rope
and then stand there and not do anything.
And so you will see - the other elephant is going to do all the work.
And in terms of cooperation, this is called "freeloading."
(Laughter)
So ... we had a freeloader.
And of course you can have only one.
If both elephants would do the same thing, nothing would happen.
So this one is just going to wait until the other one arrives.
And the other one is now going to pull it in.
(Laughter)
You will notice at the end that he doesn't forget to eat.
He's not asleep.
(Laughter)
So that's the sort of studies we do on cooperation in primates and elephants.
And we're very interested in the issue of reciprocity
because we think reciprocity underlies a lot of the evolution of cooperation,
and we study that in chimpanzees and in other primates.
So this is actually my office at the Yerkes Field Station,
which is in Lawrenceville.
These are chimpanzees who live there.
And that window up there is my view of the chimpanzees.
And so in these chimpanzees we do, for example, food sharing studies.
Here you see a food sharing scene where some chimpanzees have a watermelon.
And the male on the left,
who's reaching into the watermelon and grabbing pieces out of it,
is the alpha male of the group.
Now this is very interesting to me because the alpha male -
you would think -
could also grab the watermelon and dominate the whole situation.
But he's not doing that.
He's begging for his food.
And this has been known for a long time -
also for wild chimpanzees -
is that the highest ranking male
doesn't necessarily appropriate all the goodies in a group.
Why would that be?
I think it has to do - I wrote a book, "Chimpanzee Politics" -
Alpha males need to have a support base in the group;
otherwise, their position is very shaky.
So they need to be popular in the group.
And to be popular is to share food.
For example, if alpha males were to take all the food away from everybody,
they would probably be highly unpopular.
And then everyone would be waiting for the right occasion to topple them,
and as soon as there's a challenge, they will lose their position.
So that's why these things happen.
And it's all related to reciprocity:
deal making between males, deal making between males and females,
and that's why these things happen.
So if might is right, why would an alpha male beg?
And that has to do with reciprocity.
Let me show you one piece of evidence for reciprocity in chimpanzees.
What we do in one study is we measure in the morning
who grooms whom for how long in a group of chimpanzees.
It's very simple because they groom a lot, chimpanzees.
Then we wait a couple of hours and then we introduce food.
And if you have enough interactions over food -
so we have 7,000 interactions to work with -
you can of course statistically compare the one with the other.
You can say,
does grooming in the morning
have any effect on food sharing in the afternoon?
And that's what we find.
What we find is that if A grooms B,
then a couple of hours later, B is more likely to groom A.
It's not that B is more likely to groom anybody else.
It's not like B is in a good mood and is going to groom everybody.
No.
B is specifically sharing food
with the one who did the grooming in the morning.
So if you think about it,
what you need for this kind of mechanism is, first of all, memory.
You need to remember the grooming bout from a couple of hours ago,
which for chimpanzees is no big deal.
They remember a human face,
and I've seen this myself,
for 25 years, and so this is really simple.
But the second thing that you need
is that that memory triggers a positive attitude
toward the one who did the grooming.
And in humans we have a word for that.
We call that gratitude.
And actually, Bob Trivers, who designed the theory of reciprocal altruism,
already said, 30 years ago,
that gratitude needs to be part of the whole mechanism.
So finally, the last study I want to show you
I did with Sarah Brosnan, which is on inequality.
And now we're getting even closer to, let's say, behavioral economics.
Because this is a very big topic in behavioral economics.
And we do that on capuchin monkeys.
So we noticed with capuchin monkeys -
this is again the same apparatus that you saw before,
with a weight and two pulling bars,
and so on -
we noticed in these studies
that the capuchins are very sensitive to the reward distribution.
"Do I get more, or do I get less than somebody else?"
Now that's already very intriguing
because normally you would think anything would be fine.
Why would you watch what somebody else is getting?
What is the point of doing that?
So if any reward is better than no reward at all,
then why would you reject unfair offers?
And that's actually what we're finding in the monkeys
and certainly finding in the chimpanzees.
So the way this study was done
is that Sarah would give a token, basically a pebble, to a capuchin monkey,
who would need to hand it back.
She would hold out her hand and get it back.
And then immediately after, she would give the monkey a little piece of cucumber.
And the monkeys are perfectly fine to do that.
Any time you give them a piece of cucumber they will eat it,
so they're perfectly fine with this kind of thing.
But then we made a variation.
One monkey would still get cucumber for this exchange,
but the other one would now get grapes.
And so what is the better food?
Grapes, because they're all primates, they all go for sugar content,
so that's an old characteristic.
Actually, the food preferences of our monkeys correspond perfectly
with the prices in the supermarket.
(Laughter)
So then, here you see the exchange,
and I'm going to show you a little video clip of it.
This is a monkey watching another monkey returning the token.
This is what happens if both of them get cucumber.
There's only 5% rejections, meaning 95 -
we do like 25 trials in a row -
95% of the time they do it.
So if both get cucumber, they're fine with it.
If you give grape to the other guy, then 50% rejection,
meaning they become agitated, and they reject the food,
and they reject the pebbles.
In the third condition,
if you give the grape to the other guy without any effort,
then they go to 80% rejection.
So they're also sensitive to effort, apparently.
We've been testing this out lately.
So let me show you a little video,
and before I show it, let me say something about it.
What you see here is a monkey on the left who gets cucumber.
The monkey on the right gets grapes.
Now the cucumber and the grapes are going to be visible to them both.
You could argue - and it's been argued -
maybe they're holding out for the better food they see.
We've actually done a lot of control tests to show it's not the case.
They're really more interested in what the other monkey gets than what they see.
In this particular clip you will see that the first piece of cucumber
is happily eaten by the monkey on the left.
It's only after this guy has gotten grapes
that this one starts to object to the procedure.
So he gives a rock; he gets a piece of cucumber.
And notice that he eats it.
There it goes.
This one gives a rock, gets a grape.
The one on the left sees this, you see.
(Laughter)
Gives a rock, gets a piece of cucumber.
(Laughter)
Gives a rock...
(Laughter)
Well, this response -
in behavioral economics, or in economics in general,
you would call it an irrational response
because a piece of cucumber is better than no piece of cucumber.
So you should always accept what you can get.
This relates a bit to the ultimatum game.
Rajesh will be talking about the ultimatum game that is played with humans later.
Now recently, Sarah Brosnan found with chimpanzees,
where we're doing the same sorts of experiments,
even something more dramatic,
which I usually explain this by saying this is an egocentric sense of fairness,
only a sense of fairness that relates to "Do I get less than somebody else?"
But now recently she found in certain pairs of chimpanzees -
if you play this game -
the one who gets the grape refuses to accept the grape
until the other guy also gets a grape.
Now that gets much closer to the human full-blown sense of fairness.
And so these are so-called "irrational responses"
that we think relate to high levels of cooperation in certain animals,
like in dogs,
it has been demonstrated recently also,
which is a very cooperative group of animals.
And so in cooperative animals,
you need to watch what you get if you invest in cooperation.
You need to make sure that you don't get less -
you don't get screwed, so to speak.
You don't get less than somebody else.
So my conclusion is that primates, including Homo sapiens,
are far more social and far more cooperative
than they have been given credit for in the Homo economicus view.
And I thank you for your attention.
(Applause)