This became a very famous study and there's now many more because,

after we did this about ten years ago, it became very well known.

And we did that originally with Capuchin monkeys

and I'm going to show you the first experiment that we did.

It has now been done with dogs, and with birds, and with chimpanzees.

But we started out with Capuchin monkeys.

So what we did is we put two Capuchin monkeys side by side.

Again, these animals live in a group.

They know each other.

We take them out of the group and put them in a test chamber.

There's a very simple task that they need to do.

And if you give both of them cucumber for the task,

the two monkeys side by side,

they're perfectly willing to do this 25 times in a row.

So cucumber, even though it's really only water in my opinion, is perfectly fine for them.

Now, if you give the partner grapes...

the food preferences of my Capuchin monkeys correspond...

..exactly with the prices in the supermarket.

If you give them grapes, as a far better food,

then you create inequity between them.

So that's the experiment we did.

Recently, we videotaped it.

It was new monkeys who have never done the task,

thinking maybe they would have a stronger reaction

and that turned out to be right.

The one on the left is a monkey who gets cucumber.

The one on the right is the one who gets grapes.

The one who gets cucumber noted...

..that the first piece of cucumber is perfectly fine.

The first piece he eats.

Then she sees the other one getting grape and you will see what happens.

So she gives a rock to us. That's the task.

And we give her a piece of cucumber and she eats it.

The other one needs to give a rock to us.

And that's what she does.

And she gets a grape.

And she eats it-- the other one sees that.

She gives a rock to us now.

Gets, again, cucumber.

(audience laughs)

She tests her rock now against the wall.

She needs to give it to us.

And she gets cucumber again.

(audience laughs)

So this is basically the Wall Street protest that you see here.

(audience laughs and applauds)

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