0:00:00.562,0:00:02.815
I'm going to talk about the strategizing brain.

0:00:02.815,0:00:05.053
We're going to use an unusual combination of tools

0:00:05.053,0:00:07.066
from game theory and neuroscience

0:00:07.066,0:00:10.033
to understand how people interact socially when value is on the line.

0:00:10.033,0:00:14.004
So game theory is a branch of, originally, applied mathematics,

0:00:14.004,0:00:16.990
used mostly in economics and political science, a little bit in biology,

0:00:16.990,0:00:20.279
that gives us a mathematical taxonomy of social life

0:00:20.279,0:00:22.410
and it predicts what people are likely to do

0:00:22.410,0:00:23.604
and believe others will do

0:00:23.604,0:00:26.994
in cases where everyone's actions affect everyone else.

0:00:26.994,0:00:30.472
That's a lot of things: competition, cooperation, bargaining,

0:00:30.472,0:00:33.763
games like hide-and-seek, and poker.

0:00:33.763,0:00:36.002
Here's a simple game to get us started.

0:00:36.002,0:00:38.164
Everyone chooses a number from zero to 100,

0:00:38.164,0:00:40.610
we're going to compute the average of those numbers,

0:00:40.610,0:00:44.804
and whoever's closest to two-thirds of the average wins a fixed prize.

0:00:44.804,0:00:47.073
So you want to be a little bit below the average number,

0:00:47.073,0:00:49.309
but not too far below, and everyone else wants to be

0:00:49.309,0:00:51.254
a little bit below the average number as well.

0:00:51.254,0:00:53.833
Think about what you might pick.

0:00:53.833,0:00:57.104
As you're thinking, this is a toy model of something like

0:00:57.104,0:00:59.916
selling in the stock market during a rising market. Right?

0:00:59.916,0:01:02.141
You don't want to sell too early, because you miss out on profits,

0:01:02.141,0:01:04.321
but you don't want to wait too late

0:01:04.321,0:01:06.722
to when everyone else sells, triggering a crash.

0:01:06.722,0:01:09.601
You want to be a little bit ahead of the competition, but not too far ahead.

0:01:09.601,0:01:13.214
Okay, here's two theories about how people might think about this,

0:01:13.214,0:01:14.610
and then we'll see some data.

0:01:14.610,0:01:16.801
Some of these will sound familiar because you probably are

0:01:16.801,0:01:20.600
thinking that way. I'm using my brain theory to see.

0:01:20.600,0:01:23.710
A lot of people say, "I really don't know what people are going to pick,

0:01:23.710,0:01:25.383
so I think the average will be 50."

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They're not being really strategic at all.

0:01:27.294,0:01:30.646
"And I'll pick two-thirds of 50. That's 33." That's a start.

0:01:30.646,0:01:32.538
Other people who are a little more sophisticated,

0:01:32.538,0:01:34.014
using more working memory,

0:01:34.014,0:01:37.918
say, "I think people will pick 33 because they're going to pick a response to 50,

0:01:37.918,0:01:40.886
and so I'll pick 22, which is two-thirds of 33."

0:01:40.886,0:01:43.365
They're doing one extra step of thinking, two steps.

0:01:43.365,0:01:45.982
That's better. And of course, in principle,

0:01:45.982,0:01:47.809
you could do three, four or more,

0:01:47.809,0:01:49.678
but it starts to get very difficult.

0:01:49.678,0:01:52.270
Just like in language and other domains, we know that it's hard for people to parse

0:01:52.270,0:01:55.904
very complex sentences with a kind of recursive structure.

0:01:55.904,0:01:57.638
This is called a cognitive hierarchy theory, by the way.

0:01:57.638,0:02:00.194
It's something that I've worked on and a few other people,

0:02:00.194,0:02:02.414
and it indicates a kind of hierarchy along with

0:02:02.414,0:02:04.668
some assumptions about how many people stop at different steps

0:02:04.668,0:02:06.552
and how the steps of thinking are affected

0:02:06.552,0:02:10.248
by lots of interesting variables and variant people, as we'll see in a minute.

0:02:10.248,0:02:13.634
A very different theory, a much more popular one, and an older one,

0:02:13.634,0:02:17.174
due largely to John Nash of "A Beautiful Mind" fame,

0:02:17.174,0:02:19.414
is what's called equilibrium analysis.

0:02:19.414,0:02:21.868
So if you've ever taken a game theory course at any level,

0:02:21.868,0:02:23.581
you will have learned a little bit about this.

0:02:23.581,0:02:26.436
An equilibrium is a mathematical state in which everybody

0:02:26.436,0:02:28.885
has figured out exactly what everyone else will do.

0:02:28.885,0:02:30.892
It is a very useful concept, but behaviorally,

0:02:30.892,0:02:32.895
it may not exactly explain what people do

0:02:32.895,0:02:35.630
the first time they play these types of economic games

0:02:35.630,0:02:37.963
or in situations in the outside world.

0:02:37.963,0:02:40.301
In this case, the equilibrium makes a very bold prediction,

0:02:40.301,0:02:43.161
which is everyone wants to be below everyone else,

0:02:43.161,0:02:45.452
therefore they'll play zero.

0:02:45.452,0:02:48.461
Let's see what happens. This experiment's been done many, many times.

0:02:48.461,0:02:50.344
Some of the earliest ones were done in the '90s

0:02:50.344,0:02:52.989
by me and Rosemarie Nagel and others.

0:02:52.989,0:02:55.974
This is a beautiful data set of 9,000 people who wrote in

0:02:55.974,0:02:58.854
to three newspapers and magazines that had a contest.

0:02:58.854,0:03:00.668
The contest said, send in your numbers

0:03:00.668,0:03:03.823
and whoever is close to two-thirds of the average will win a big prize.

0:03:03.823,0:03:06.911
And as you can see, there's so much data here, you can see the spikes very visibly.

0:03:06.911,0:03:10.292
There's a spike at 33. Those are people doing one step.

0:03:10.292,0:03:12.789
There is another spike visible at 22.

0:03:12.789,0:03:15.081
And notice, by the way, that most people pick numbers right around there.

0:03:15.081,0:03:17.591
They don't necessarily pick exactly 33 and 22.

0:03:17.591,0:03:19.647
There's something a little bit noisy around it.

0:03:19.647,0:03:21.125
But you can see those spikes, and they're there.

0:03:21.125,0:03:22.835
There's another group of people who seem to have

0:03:22.835,0:03:24.910
a firm grip on equilibrium analysis,

0:03:24.910,0:03:27.305
because they're picking zero or one.

0:03:27.305,0:03:29.394
But they lose, right?

0:03:29.394,0:03:32.586
Because picking a number that low is actually a bad choice

0:03:32.586,0:03:35.406
if other people aren't doing equilibrium analysis as well.

0:03:35.406,0:03:37.518
So they're smart, but poor.

0:03:37.518,0:03:39.606
(Laughter)

0:03:39.606,0:03:41.575
Where are these things happening in the brain?

0:03:41.575,0:03:45.450
One study by Coricelli and Nagel gives a really sharp, interesting answer.

0:03:45.450,0:03:46.958
So they had people play this game

0:03:46.958,0:03:49.175
while they were being scanned in an fMRI,

0:03:49.175,0:03:51.446
and two conditions: in some trials,

0:03:51.446,0:03:52.961
they're told you're playing another person

0:03:52.961,0:03:54.549
who's playing right now and we're going to match up

0:03:54.549,0:03:56.753
your behavior at the end and pay you if you win.

0:03:56.753,0:03:58.731
In the other trials, they're told, you're playing a computer.

0:03:58.731,0:04:00.365
They're just choosing randomly.

0:04:00.365,0:04:02.442
So what you see here is a subtraction

0:04:02.442,0:04:05.192
of areas in which there's more brain activity

0:04:05.192,0:04:08.168
when you're playing people compared to playing the computer.

0:04:08.168,0:04:10.159
And you see activity in some regions we've seen today,

0:04:10.159,0:04:13.396
medial prefrontal cortex, dorsomedial, however, up here,

0:04:13.396,0:04:15.247
ventromedial prefrontal cortex,

0:04:15.247,0:04:16.601
anterior cingulate, an area that's involved

0:04:16.601,0:04:20.238
in lots of types of conflict resolution, like if you're playing "Simon Says,"

0:04:20.238,0:04:24.052
and also the right and left temporoparietal junction.

0:04:24.052,0:04:26.518
And these are all areas which are fairly reliably known

0:04:26.518,0:04:28.839
to be part of what's called a "theory of mind" circuit,

0:04:28.839,0:04:30.740
or "mentalizing circuit."

0:04:30.740,0:04:34.118
That is, it's a circuit that's used to imagine what other people might do.

0:04:34.118,0:04:36.358
So these were some of the first studies to see this

0:04:36.358,0:04:38.391
tied in to game theory.

0:04:38.391,0:04:40.631
What happens with these one- and two-step types?

0:04:40.631,0:04:42.702
So we classify people by what they picked,

0:04:42.702,0:04:44.369
and then we look at the difference between

0:04:44.369,0:04:46.344
playing humans versus playing computers,

0:04:46.344,0:04:48.235
which brain areas are differentially active.

0:04:48.235,0:04:49.987
On the top you see the one-step players.

0:04:49.987,0:04:51.507
There's almost no difference.

0:04:51.507,0:04:54.447
The reason is, they're treating other people like a computer, and the brain is too.

0:04:54.447,0:04:58.588
The bottom players, you see all the activity in dorsomedial PFC.

0:04:58.588,0:05:00.639
So we know that those two-step players are doing something differently.

0:05:00.639,0:05:03.735
Now if you were to step back and say, "What can we do with this information?"

0:05:03.735,0:05:05.556
you might be able to look at brain activity and say,

0:05:05.556,0:05:07.055
"This person's going to be a good poker player,"

0:05:07.055,0:05:08.984
or, "This person's socially naive,"

0:05:08.984,0:05:10.262
and we might also be able to study things

0:05:10.262,0:05:11.860
like development of adolescent brains

0:05:11.860,0:05:15.214
once we have an idea of where this circuitry exists.

0:05:15.214,0:05:17.826
Okay. Get ready.

0:05:17.826,0:05:19.949
I'm saving you some brain activity,

0:05:19.949,0:05:22.759
because you don't need to use your hair detector cells.

0:05:22.759,0:05:25.647
You should use those cells to think carefully about this game.

0:05:25.647,0:05:27.582
This is a bargaining game.

0:05:27.582,0:05:30.138
Two players who are being scanned using EEG electrodes

0:05:30.138,0:05:33.015
are going to bargain over one to six dollars.

0:05:33.015,0:05:35.679
If they can do it in 10 seconds, they're going to actually earn that money.

0:05:35.679,0:05:38.719
If 10 seconds goes by and they haven't made a deal, they get nothing.

0:05:38.719,0:05:40.402
That's kind of a mistake together.

0:05:40.402,0:05:43.219
The twist is that one player, on the left,

0:05:43.219,0:05:45.907
is informed about how much on each trial there is.

0:05:45.907,0:05:48.139
They play lots of trials with different amounts each time.

0:05:48.139,0:05:50.380
In this case, they know there's four dollars.

0:05:50.380,0:05:52.257
The uninformed player doesn't know,

0:05:52.257,0:05:54.311
but they know that the informed player knows.

0:05:54.311,0:05:56.370
So the uninformed player's challenge is to say,

0:05:56.370,0:05:57.840
"Is this guy really being fair

0:05:57.840,0:05:59.694
or are they giving me a very low offer

0:05:59.694,0:06:02.772
in order to get me to think that there's only one or two dollars available to split?"

0:06:02.772,0:06:05.926
in which case they might reject it and not come to a deal.

0:06:05.926,0:06:08.876
So there's some tension here between trying to get the most money

0:06:08.876,0:06:11.449
but trying to goad the other player into giving you more.

0:06:11.449,0:06:13.779
And the way they bargain is to point on a number line

0:06:13.779,0:06:15.585
that goes from zero to six dollars,

0:06:15.585,0:06:18.563
and they're bargaining over how much the uninformed player gets,

0:06:18.563,0:06:20.148
and the informed player's going to get the rest.

0:06:20.148,0:06:22.723
So this is like a management-labor negotiation

0:06:22.723,0:06:25.456
in which the workers don't know how much profits

0:06:25.456,0:06:28.123
the privately held company has, right,

0:06:28.123,0:06:30.491
and they want to maybe hold out for more money,

0:06:30.491,0:06:32.327
but the company might want to create the impression

0:06:32.327,0:06:35.259
that there's very little to split: "I'm giving you the most that I can."

0:06:35.259,0:06:39.490
First some behavior. So a bunch of the subject pairs, they play face to face.

0:06:39.490,0:06:41.326
We have some other data where they play across computers.

0:06:41.326,0:06:43.064
That's an interesting difference, as you might imagine.

0:06:43.064,0:06:45.266
But a bunch of the face-to-face pairs

0:06:45.266,0:06:48.959
agree to divide the money evenly every single time.

0:06:48.959,0:06:51.865
Boring. It's just not interesting neurally.

0:06:51.865,0:06:54.379
It's good for them. They make a lot of money.

0:06:54.379,0:06:57.051
But we're interested in, can we say something about

0:06:57.051,0:06:59.587
when disagreements occur versus don't occur?

0:06:59.587,0:07:01.944
So this is the other group of subjects who often disagree.

0:07:01.944,0:07:04.712
So they have a chance of -- they bicker and disagree

0:07:04.712,0:07:06.019
and end up with less money.

0:07:06.019,0:07:09.936
They might be eligible to be on "Real Housewives," the TV show.

0:07:09.936,0:07:11.872
You see on the left,

0:07:11.872,0:07:14.536
when the amount to divide is one, two or three dollars,

0:07:14.536,0:07:16.184
they disagree about half the time,

0:07:16.184,0:07:18.376
and when the amount is four, five, six, they agree quite often.

0:07:18.376,0:07:20.250
This turns out to be something that's predicted

0:07:20.250,0:07:22.454
by a very complicated type of game theory

0:07:22.454,0:07:25.263
you should come to graduate school at CalTech and learn about.

0:07:25.263,0:07:27.435
It's a little too complicated to explain right now,

0:07:27.435,0:07:30.851
but the theory tells you that this shape kind of should occur.

0:07:30.851,0:07:33.067
Your intuition might tell you that too.

0:07:33.067,0:07:35.307
Now I'm going to show you the results from the EEG recording.

0:07:35.307,0:07:37.660
Very complicated. The right brain schematic

0:07:37.660,0:07:40.523
is the uninformed person, and the left is the informed.

0:07:40.523,0:07:43.323
Remember that we scanned both brains at the same time,

0:07:43.323,0:07:45.715
so we can ask about time-synced activity

0:07:45.715,0:07:48.939
in similar or different areas simultaneously,

0:07:48.939,0:07:51.203
just like if you wanted to study a conversation

0:07:51.203,0:07:53.139
and you were scanning two people talking to each other

0:07:53.139,0:07:55.499
and you'd expect common activity in language regions

0:07:55.499,0:07:57.884
when they're actually kind of listening and communicating.

0:07:57.884,0:08:01.811
So the arrows connect regions that are active at the same time,

0:08:01.811,0:08:03.851
and the direction of the arrows flows

0:08:03.851,0:08:06.331
from the region that's active first in time,

0:08:06.331,0:08:09.899
and the arrowhead goes to the region that's active later.

0:08:09.899,0:08:12.115
So in this case, if you look carefully,

0:08:12.115,0:08:13.972
most of the arrows flow from right to left.

0:08:13.972,0:08:17.252
That is, it looks as if the uninformed brain activity

0:08:17.252,0:08:19.211
is happening first,

0:08:19.211,0:08:22.726
and then it's followed by activity in the informed brain.

0:08:22.726,0:08:26.418
And by the way, these were trials where their deals were made.

0:08:26.418,0:08:28.198
This is from the first two seconds.

0:08:28.198,0:08:30.178
We haven't finished analyzing this data,

0:08:30.178,0:08:32.078
so we're still peeking in, but the hope is

0:08:32.078,0:08:34.642
that we can say something in the first couple of seconds

0:08:34.642,0:08:36.365
about whether they'll make a deal or not,

0:08:36.365,0:08:38.408
which could be very useful in thinking about avoiding litigation

0:08:38.408,0:08:40.336
and ugly divorces and things like that.

0:08:40.336,0:08:43.219
Those are all cases in which a lot of value is lost

0:08:43.219,0:08:46.195
by delay and strikes.

0:08:46.195,0:08:48.225
Here's the case where the disagreements occur.

0:08:48.225,0:08:50.398
You can see it looks different than the one before.

0:08:50.398,0:08:52.647
There's a lot more arrows.

0:08:52.647,0:08:54.158
That means that the brains are synced up

0:08:54.158,0:08:56.710
more closely in terms of simultaneous activity,

0:08:56.710,0:08:58.720
and the arrows flow clearly from left to right.

0:08:58.720,0:09:00.962
That is, the informed brain seems to be deciding,

0:09:00.962,0:09:03.250
"We're probably not going to make a deal here."

0:09:03.250,0:09:06.475
And then later there's activity in the uninformed brain.

0:09:06.475,0:09:08.978
Next I'm going to introduce you to some relatives.

0:09:08.978,0:09:11.239
They're hairy, smelly, fast and strong.

0:09:11.239,0:09:14.429
You might be thinking back to your last Thanksgiving.

0:09:14.429,0:09:17.122
Maybe if you had a chimpanzee with you.

0:09:17.122,0:09:20.583
Charles Darwin and I and you broke off from the family tree

0:09:20.583,0:09:22.842
from chimpanzees about five million years ago.

0:09:22.842,0:09:24.810
They're still our closest genetic kin.

0:09:24.810,0:09:26.547
We share 98.8 percent of the genes.

0:09:26.547,0:09:29.347
We share more genes with them than zebras do with horses.

0:09:29.347,0:09:31.064
And we're also their closest cousin.

0:09:31.064,0:09:34.066
They have more genetic relation to us than to gorillas.

0:09:34.066,0:09:36.594
So how humans and chimpanzees behave differently

0:09:36.594,0:09:39.049
might tell us a lot about brain evolution.

0:09:39.049,0:09:41.650
So this is an amazing memory test

0:09:41.650,0:09:44.466
from Nagoya, Japan, Primate Research Institute,

0:09:44.466,0:09:46.244
where they've done a lot of this research.

0:09:46.244,0:09:48.584
This goes back quite a ways. They're interested in working memory.

0:09:48.584,0:09:50.356
The chimp is going to see, watch carefully,

0:09:50.356,0:09:52.558
they're going to see 200 milliseconds' exposure

0:09:52.558,0:09:54.552
— that's fast, that's eight movie frames —

0:09:54.552,0:09:56.503
of numbers one, two, three, four, five.

0:09:56.503,0:09:58.501
Then they disappear and they're replaced by squares,

0:09:58.501,0:10:00.256
and they have to press the squares

0:10:00.256,0:10:02.577
that correspond to the numbers from low to high

0:10:02.577,0:10:03.916
to get an apple reward.

0:10:03.916,0:10:08.687
Let's see how they can do it.

0:10:16.391,0:10:17.884
This is a young chimp. The young ones

0:10:17.884,0:10:20.667
are better than the old ones, just like humans.

0:10:20.667,0:10:22.259
And they're highly experienced, so they've done this

0:10:22.259,0:10:23.691
thousands and thousands of time.

0:10:23.691,0:10:26.575
Obviously there's a big training effect, as you can imagine.

0:10:27.928,0:10:29.272
(Laughter)

0:10:29.272,0:10:31.207
You can see they're very blasé and kind of effortless.

0:10:31.207,0:10:35.135
Not only can they do it very well, they do it in a sort of lazy way.

0:10:35.135,0:10:38.570
Right? Who thinks you could beat the chimps?

0:10:38.570,0:10:40.166
Wrong. (Laughter)

0:10:40.166,0:10:42.604
We can try. We'll try. Maybe we'll try.

0:10:42.604,0:10:45.194
Okay, so the next part of this study

0:10:45.194,0:10:46.790
I'm going to go quickly through

0:10:46.790,0:10:49.482
is based on an idea of Tetsuro Matsuzawa.

0:10:49.482,0:10:52.511
He had a bold idea that -- what he called the cognitive trade-off hypothesis.

0:10:52.511,0:10:53.803
We know chimps are faster and stronger.

0:10:53.803,0:10:55.483
They're also very obsessed with status.

0:10:55.483,0:10:58.439
His thought was, maybe they've preserved brain activities

0:10:58.439,0:11:00.607
and they practice them in development

0:11:00.607,0:11:02.458
that are really, really important to them

0:11:02.458,0:11:04.668
to negotiate status and to win,

0:11:04.668,0:11:07.666
which is something like strategic thinking during competition.

0:11:07.666,0:11:09.246
So we're going to check that out

0:11:09.246,0:11:11.676
by having the chimps actually play a game

0:11:11.676,0:11:14.314
by touching two touch screens.

0:11:14.314,0:11:16.754
The chimps are actually interacting with each other through the computers.

0:11:16.754,0:11:18.362
They're going to press left or right.

0:11:18.362,0:11:20.475
One chimp is called a matcher.

0:11:20.475,0:11:22.458
They win if they press left, left,

0:11:22.458,0:11:25.627
like a seeker finding someone in hide-and-seek, or right, right.

0:11:25.627,0:11:26.855
The mismatcher wants to mismatch.

0:11:26.855,0:11:29.931
They want to press the opposite screen of the chimp.

0:11:29.931,0:11:32.475
And the rewards are apple cube rewards.

0:11:32.475,0:11:35.003
So here's how game theorists look at these data.

0:11:35.003,0:11:36.617
This is a graph of the percentage of times

0:11:36.617,0:11:39.235
the matcher picked right on the x-axis,

0:11:39.235,0:11:40.751
and the percentage of times they predicted right

0:11:40.751,0:11:43.619
by the mismatcher on the y-axis.

0:11:43.619,0:11:46.819
So a point here is the behavior by a pair of players,

0:11:46.819,0:11:49.035
one trying to match, one trying to mismatch.

0:11:49.035,0:11:52.315
The NE square in the middle -- actually NE, CH and QRE --

0:11:52.315,0:11:54.771
those are three different theories of Nash equilibrium, and others,

0:11:54.771,0:11:57.195
tells you what the theory predicts,

0:11:57.195,0:11:59.467
which is that they should match 50-50,

0:11:59.467,0:12:01.635
because if you play left too much, for example,

0:12:01.635,0:12:04.351
I can exploit that if I'm the mismatcher by then playing right.

0:12:04.351,0:12:07.115
And as you can see, the chimps, each chimp is one triangle,

0:12:07.115,0:12:10.962
are circled around, hovering around that prediction.

0:12:10.962,0:12:12.736
Now we move the payoffs.

0:12:12.736,0:12:16.179
We're actually going to make the left, left payoff for the matcher a little bit higher.

0:12:16.179,0:12:17.699
Now they get three apple cubes.

0:12:17.699,0:12:20.499
Game theoretically, that should actually make the mismatcher's behavior shift,

0:12:20.499,0:12:22.089
because what happens is, the mismatcher will think,

0:12:22.089,0:12:23.899
oh, this guy's going to go for the big reward,

0:12:23.899,0:12:26.964
and so I'm going to go to the right, make sure he doesn't get it.

0:12:26.964,0:12:28.629
And as you can see, their behavior moves up

0:12:28.629,0:12:32.077
in the direction of this change in the Nash equilibrium.

0:12:32.077,0:12:34.391
Finally, we changed the payoffs one more time.

0:12:34.391,0:12:35.583
Now it's four apple cubes,

0:12:35.583,0:12:37.755
and their behavior again moves towards the Nash equilibrium.

0:12:37.755,0:12:39.790
It's sprinkled around, but if you average the chimps out,

0:12:39.790,0:12:41.980
they're really, really close, within .01.

0:12:41.980,0:12:45.179
They're actually closer than any species we've observed.

0:12:45.179,0:12:48.372
What about humans? You think you're smarter than a chimpanzee?

0:12:48.372,0:12:51.939
Here's two human groups in green and blue.

0:12:51.939,0:12:55.683
They're closer to 50-50. They're not responding to payoffs as closely,

0:12:55.683,0:12:57.133
and also if you study their learning in the game,

0:12:57.133,0:12:59.118
they aren't as sensitive to previous rewards.

0:12:59.118,0:13:00.482
The chimps are playing better than the humans,

0:13:00.482,0:13:02.905
better in the sense of adhering to game theory.

0:13:02.905,0:13:04.324
And these are two different groups of humans

0:13:04.324,0:13:07.520
from Japan and Africa. They replicate quite nicely.

0:13:07.520,0:13:10.755
None of them are close to where the chimps are.

0:13:10.755,0:13:12.510
So here are some things we learned today.

0:13:12.510,0:13:14.448
People seem to do a limited amount of strategic thinking

0:13:14.448,0:13:16.259
using theory of mind.

0:13:16.259,0:13:18.176
We have some preliminary evidence from bargaining

0:13:18.176,0:13:20.668
that early warning signs in the brain might be used to predict

0:13:20.668,0:13:22.894
whether there will be a bad disagreement that costs money,

0:13:22.894,0:13:24.734
and chimps are better competitors than humans,

0:13:24.734,0:13:27.198
as judged by game theory.

0:13:27.198,0:13:29.055
Thank you.

0:13:29.055,0:13:32.628
(Applause)