Paul Zak: Trust, morality - and oxytocin

350,635 views ・ 2011-11-01

TED


Please double-click on the English subtitles below to play the video.

00:15
Is there anything unique about human beings?
0
15260
3000
00:18
There is.
1
18260
2000
00:20
We're the only creatures
2
20260
2000
00:22
with fully developed moral sentiments.
3
22260
2000
00:24
We're obsessed with morality as social creatures.
4
24260
3000
00:27
We need to know why people are doing what they're doing.
5
27260
3000
00:30
And I personally am obsessed with morality.
6
30260
3000
00:33
It was all due to this woman,
7
33260
2000
00:35
Sister Mary Marastela,
8
35260
2000
00:37
also known as my mom.
9
37260
3000
00:41
As an altar boy, I breathed in a lot of incense,
10
41260
3000
00:44
and I learned to say phrases in Latin,
11
44260
2000
00:46
but I also had time to think
12
46260
2000
00:48
about whether my mother's top-down morality
13
48260
2000
00:50
applied to everybody.
14
50260
2000
00:52
I saw that people who were religious and non-religious
15
52260
3000
00:55
were equally obsessed with morality.
16
55260
2000
00:57
I thought, maybe there's some earthly basis
17
57260
2000
00:59
for moral decisions.
18
59260
2000
01:01
But I wanted to go further
19
61260
2000
01:03
than to say our brains make us moral.
20
63260
2000
01:05
I want to know if there's a chemistry of morality.
21
65260
3000
01:08
I want to know
22
68260
2000
01:10
if there was a moral molecule.
23
70260
2000
01:12
After 10 years of experiments,
24
72260
2000
01:14
I found it.
25
74260
2000
01:16
Would you like to see it? I brought some with me.
26
76260
3000
01:20
This little syringe
27
80260
2000
01:22
contains the moral molecule.
28
82260
3000
01:31
(Laughter)
29
91260
3000
01:34
It's called oxytocin.
30
94260
2000
01:36
So oxytocin is a simple and ancient molecule
31
96260
3000
01:39
found only in mammals.
32
99260
2000
01:41
In rodents, it was known
33
101260
2000
01:43
to make mothers care for their offspring,
34
103260
2000
01:45
and in some creatures,
35
105260
2000
01:47
allowed for toleration of burrowmates.
36
107260
2000
01:49
But in humans, it was only known
37
109260
2000
01:51
to facilitate birth and breastfeeding in women,
38
111260
2000
01:53
and is released by both sexes during sex.
39
113260
3000
01:57
So I had this idea that oxytocin might be the moral molecule.
40
117260
3000
02:00
I did what most of us do -- I tried it on some colleagues.
41
120260
3000
02:03
One of them told me,
42
123260
2000
02:05
"Paul, that is the world's stupidist idea.
43
125260
3000
02:08
It is," he said, "only a female molecule.
44
128260
2000
02:10
It can't be that important."
45
130260
2000
02:12
But I countered, "Well men's brains make this too.
46
132260
3000
02:15
There must be a reason why."
47
135260
2000
02:17
But he was right, it was a stupid idea.
48
137260
3000
02:20
But it was testably stupid.
49
140260
2000
02:22
In other words, I thought I could design an experiment
50
142260
3000
02:25
to see if oxytocin made people moral.
51
145260
3000
02:29
Turns out it wasn't so easy.
52
149260
2000
02:31
First of all, oxytocin is a shy molecule.
53
151260
3000
02:34
Baseline levels are near zero,
54
154260
2000
02:36
without some stimulus to cause its release.
55
156260
3000
02:39
And when it's produced, it has a three-minute half-life,
56
159260
2000
02:41
and degrades rapidly at room temperature.
57
161260
3000
02:44
So this experiment would have to cause a surge of oxytocin,
58
164260
2000
02:46
have to grab it fast and keep it cold.
59
166260
2000
02:48
I think I can do that.
60
168260
2000
02:50
Now luckily, oxytocin is produced
61
170260
2000
02:52
both in the brain and in the blood,
62
172260
3000
02:55
so I could do this experiment without learning neurosurgery.
63
175260
3000
02:59
Then I had to measure morality.
64
179260
3000
03:02
So taking on Morality with a capital M is a huge project.
65
182260
3000
03:05
So I started smaller.
66
185260
2000
03:07
I studied one single virtue:
67
187260
3000
03:10
trustworthiness.
68
190260
2000
03:12
Why? I had shown in the early 2000s
69
192260
3000
03:15
that countries with a higher proportion of trustworthy people
70
195260
3000
03:18
are more prosperous.
71
198260
2000
03:20
So in these countries, more economic transactions occur
72
200260
3000
03:23
and more wealth is created,
73
203260
2000
03:25
alleviating poverty.
74
205260
2000
03:27
So poor countries are by and large low trust countries.
75
207260
3000
03:30
So if I understood the chemistry of trustworthiness,
76
210260
3000
03:33
I might help alleviate poverty.
77
213260
2000
03:35
But I'm also a skeptic.
78
215260
2000
03:37
I don't want to just ask people, "Are you trustworthy?"
79
217260
2000
03:39
So instead I use
80
219260
2000
03:41
the Jerry Maguire approach to research.
81
221260
2000
03:43
If you're so virtuous,
82
223260
2000
03:45
show me the money.
83
225260
2000
03:47
So what we do in my lab
84
227260
2000
03:49
is we tempt people with virtue and vice by using money.
85
229260
2000
03:51
Let me show you how we do that.
86
231260
2000
03:53
So we recruit some people for an experiment.
87
233260
2000
03:55
They all get $10 if they agree to show up.
88
235260
3000
03:58
We give them lots of instruction, and we never ever deceive them.
89
238260
3000
04:01
Then we match them in pairs by computer.
90
241260
3000
04:04
And in that pair, one person gets a message saying,
91
244260
2000
04:06
"Do you want to give up some of your $10
92
246260
2000
04:08
you earned for being here
93
248260
2000
04:10
and ship it to someone else in the lab?"
94
250260
2000
04:12
The trick is you can't see them,
95
252260
2000
04:14
you can't talk to them.
96
254260
2000
04:16
You only do it one time.
97
256260
2000
04:18
Now whatever you give up
98
258260
2000
04:20
gets tripled in the other person's account.
99
260260
3000
04:23
You're going to make them a lot wealthier.
100
263260
2000
04:25
And they get a message by computer saying
101
265260
2000
04:27
person one sent you this amount of money.
102
267260
2000
04:29
Do you want to keep it all,
103
269260
2000
04:31
or do you want to send some amount back?
104
271260
3000
04:34
So think about this experiment for minute.
105
274260
2000
04:36
You're going to sit on these hard chairs for an hour and a half.
106
276260
3000
04:39
Some mad scientist is going to jab your arm with a needle
107
279260
2000
04:41
and take four tubes of blood.
108
281260
2000
04:43
And now you want me to give up this money and ship it to a stranger?
109
283260
3000
04:46
So this was the birth of vampire economics.
110
286260
3000
04:49
Make a decision and give me some blood.
111
289260
3000
04:52
So in fact, experimental economists
112
292260
2000
04:54
had run this test around the world,
113
294260
2000
04:56
and for much higher stakes,
114
296260
2000
04:58
and the consensus view
115
298260
2000
05:00
was that the measure from the first person to the second was a measure of trust,
116
300260
3000
05:03
and the transfer from the second person back to the first
117
303260
3000
05:06
measured trustworthiness.
118
306260
2000
05:08
But in fact, economists were flummoxed
119
308260
2000
05:10
on why the second person would ever return any money.
120
310260
3000
05:13
They assumed money is good,
121
313260
2000
05:15
why not keep it all?
122
315260
2000
05:17
That's not what we found.
123
317260
2000
05:19
We found 90 percent of the first decision-makers sent money,
124
319260
3000
05:22
and of those who received money,
125
322260
2000
05:24
95 percent returned some of it.
126
324260
2000
05:26
But why?
127
326260
2000
05:28
Well by measuring oxytocin
128
328260
2000
05:30
we found that the more money the second person received,
129
330260
2000
05:32
the more their brain produced oxytocin,
130
332260
2000
05:34
and the more oxytocin on board,
131
334260
2000
05:36
the more money they returned.
132
336260
3000
05:39
So we have a biology of trustworthiness.
133
339260
3000
05:42
But wait. What's wrong with this experiment?
134
342260
3000
05:45
Two things.
135
345260
2000
05:47
One is that nothing in the body happens in isolation.
136
347260
3000
05:50
So we measured nine other molecules that interact with oxytocin,
137
350260
3000
05:53
but they didn't have any effect.
138
353260
2000
05:55
But the second is
139
355260
2000
05:57
that I still only had this indirect relationship
140
357260
2000
05:59
between oxytocin and trustworthiness.
141
359260
2000
06:01
I didn't know for sure
142
361260
2000
06:03
oxytocin caused trustworthiness.
143
363260
2000
06:05
So to make the experiment,
144
365260
2000
06:07
I knew I'd have to go into the brain
145
367260
2000
06:09
and manipulate oxytocin directly.
146
369260
2000
06:11
I used everything short of a drill
147
371260
2000
06:13
to get oxytocin into my own brain.
148
373260
3000
06:16
And I found I could do it
149
376260
2000
06:18
with a nasal inhaler.
150
378260
2000
06:20
So along with colleagues in Zurich,
151
380260
2000
06:22
we put 200 men on oxytocin or placebo,
152
382260
2000
06:24
had that same trust test with money,
153
384260
2000
06:26
and we found that those on oxytocin not only showed more trust,
154
386260
3000
06:29
we can more than double the number of people
155
389260
3000
06:32
who sent all their money to a stranger --
156
392260
2000
06:34
all without altering mood or cognition.
157
394260
3000
06:38
So oxytocin is the trust molecule,
158
398260
4000
06:42
but is it the moral molecule?
159
402260
3000
06:45
Using the oxytocin inhaler,
160
405260
2000
06:47
we ran more studies.
161
407260
2000
06:49
We showed that oxytocin infusion
162
409260
2000
06:51
increases generosity
163
411260
2000
06:53
in unilateral monetary transfers
164
413260
2000
06:55
by 80 percent.
165
415260
2000
06:57
We showed it increases donations to charity
166
417260
2000
06:59
by 50 percent.
167
419260
2000
07:01
We've also investigated
168
421260
2000
07:03
non-pharmacologic ways to raise oxytocin.
169
423260
2000
07:05
These include massage,
170
425260
2000
07:07
dancing and praying.
171
427260
2000
07:09
Yes, my mom was happy about that last one.
172
429260
3000
07:12
And whenever we raise oxytocin,
173
432260
2000
07:14
people willingly open up their wallets
174
434260
2000
07:16
and share money with strangers.
175
436260
2000
07:18
But why do they do this?
176
438260
2000
07:20
What does it feel like
177
440260
2000
07:22
when your brain is flooded with oxytocin?
178
442260
2000
07:24
To investigate this question, we ran an experiment
179
444260
3000
07:27
where we had people watch a video
180
447260
2000
07:29
of a father and his four year-old son,
181
449260
2000
07:31
and his son has terminal brain cancer.
182
451260
2000
07:33
After they watched the video, we had them rate their feelings
183
453260
3000
07:36
and took blood before and after to measure oxytocin.
184
456260
3000
07:39
The change in oxytocin
185
459260
2000
07:41
predicted their feelings of empathy.
186
461260
3000
07:45
So it's empathy
187
465260
2000
07:47
that makes us connect to other people.
188
467260
2000
07:49
It's empathy that makes us help other people.
189
469260
3000
07:52
It's empathy that makes us moral.
190
472260
4000
07:56
Now this idea is not new.
191
476260
2000
07:58
A then unknown philosopher named Adam Smith
192
478260
2000
08:00
wrote a book in 1759
193
480260
2000
08:02
called "The Theory of Moral Sentiments."
194
482260
2000
08:04
In this book, Smith argued
195
484260
3000
08:07
that we are moral creatures, not because of a top-down reason,
196
487260
3000
08:10
but for a bottom-up reason.
197
490260
2000
08:12
He said we're social creatures,
198
492260
2000
08:14
so we share the emotions of others.
199
494260
2000
08:16
So if I do something that hurts you, I feel that pain.
200
496260
3000
08:19
So I tend to avoid that.
201
499260
2000
08:21
If I do something that makes you happy, I get to share your joy.
202
501260
3000
08:24
So I tend to do those things.
203
504260
2000
08:26
Now this is the same Adam Smith who, 17 years later,
204
506260
2000
08:28
would write a little book called "The Wealth of Nations" --
205
508260
3000
08:31
the founding document of economics.
206
511260
2000
08:33
But he was, in fact, a moral philosopher,
207
513260
3000
08:36
and he was right on why we're moral.
208
516260
2000
08:38
I just found the molecule behind it.
209
518260
3000
08:41
But knowing that molecule is valuable,
210
521260
3000
08:44
because it tells us how to turn up this behavior
211
524260
3000
08:47
and what turns it off.
212
527260
2000
08:49
In particular, it tells us
213
529260
2000
08:51
why we see immorality.
214
531260
3000
08:54
So to investigate immorality,
215
534260
2000
08:56
let me bring you back now to 1980.
216
536260
2000
08:58
I'm working at a gas station
217
538260
2000
09:00
on the outskirts of Santa Barbara, California.
218
540260
3000
09:03
You sit in a gas station all day,
219
543260
2000
09:05
you see lots of morality and immorality, let me tell you.
220
545260
2000
09:07
So one Sunday afternoon, a man walks into my cashier's booth
221
547260
3000
09:10
with this beautiful jewelry box.
222
550260
2000
09:12
Opens it up and there's a pearl necklace inside.
223
552260
2000
09:14
And he said, "Hey, I was in the men's room.
224
554260
2000
09:16
I just found this. What do you think we should do with it?"
225
556260
3000
09:19
"I don't know, put it in the lost and found."
226
559260
2000
09:21
"Well this is very valuable.
227
561260
2000
09:23
We have to find the owner for this." I said, "Yea."
228
563260
2000
09:25
So we're trying to decide what to do with this,
229
565260
2000
09:27
and the phone rings.
230
567260
2000
09:29
And a man says very excitedly,
231
569260
2000
09:31
"I was in your gas station a while ago,
232
571260
2000
09:33
and I bought this jewelry for my wife, and I can't find it."
233
573260
2000
09:35
I said, "Pearl necklace?" "Yeah."
234
575260
2000
09:37
"Hey, a guy just found it."
235
577260
2000
09:39
"Oh, you're saving my life. Here's my phone number.
236
579260
2000
09:41
Tell that guy to wait half an hour.
237
581260
2000
09:43
I'll be there and I'll give him a $200 reward."
238
583260
2000
09:45
Great, so I tell the guy, "Look, relax.
239
585260
2000
09:47
Get yourself a fat reward. Life's good."
240
587260
3000
09:50
He said, "I can't do it.
241
590260
2000
09:52
I have this job interview in Galena in 15 minutes,
242
592260
2000
09:54
and I need this job, I've got to go."
243
594260
3000
09:57
Again he asked me, "What do you think we should do?"
244
597260
2000
09:59
I'm in high school. I have no idea.
245
599260
3000
10:02
So I said, "I'll hold it for you."
246
602260
2000
10:04
He said, "You know, you've been so nice, let's split the reward."
247
604260
3000
10:07
I'll give you the jewelry, you give me a hundred dollars,
248
607260
2000
10:09
and when the guy comes ... "
249
609260
2000
10:11
You see it. I was conned.
250
611260
2000
10:13
So this is a classic con called the pigeon drop,
251
613260
3000
10:16
and I was the pigeon.
252
616260
2000
10:18
So the way many cons work
253
618260
2000
10:20
is not that the conman gets the victim to trust him,
254
620260
3000
10:23
it's that he shows he trusts the victim.
255
623260
3000
10:26
Now we know what happens.
256
626260
2000
10:28
The victim's brain releases oxytocin,
257
628260
2000
10:30
and you're opening up your wallet or purse, giving away the money.
258
630260
3000
10:33
So who are these people
259
633260
2000
10:35
who manipulate our oxytocin systems?
260
635260
3000
10:38
We found, testing thousands of individuals,
261
638260
3000
10:41
that five percent of the population
262
641260
2000
10:43
don't release oxytocin on stimulus.
263
643260
3000
10:47
So if you trust them, their brains don't release oxytocin.
264
647260
3000
10:50
If there's money on the table, they keep it all.
265
650260
3000
10:53
So there's a technical word for these people in my lab.
266
653260
2000
10:55
We call them bastards.
267
655260
3000
10:58
(Laughter)
268
658260
2000
11:00
These are not people you want to have a beer with.
269
660260
2000
11:02
They have many of the attributes of psychopaths.
270
662260
3000
11:06
Now there are other ways the system can be inhibited.
271
666260
2000
11:08
One is through improper nurturing.
272
668260
3000
11:11
So we've studied sexually abused women,
273
671260
3000
11:14
and about half those don't release oxytocin on stimulus.
274
674260
3000
11:17
You need enough nurturing
275
677260
2000
11:19
for this system to develop properly.
276
679260
2000
11:21
Also, high stress inhibits oxytocin.
277
681260
3000
11:24
So we all know this, when we're really stressed out,
278
684260
2000
11:26
we're not acting our best.
279
686260
3000
11:29
There's another way oxytocin is inhibited, which is interesting --
280
689260
3000
11:32
through the action of testosterone.
281
692260
3000
11:35
So we, in experiments, have administered testosterone to men.
282
695260
3000
11:38
And instead of sharing money,
283
698260
2000
11:40
they become selfish.
284
700260
2000
11:42
But interestingly,
285
702260
3000
11:45
high testosterone males are also more likely
286
705260
2000
11:47
to use their own money to punish others for being selfish.
287
707260
3000
11:50
(Laughter)
288
710260
2000
11:52
Now think about this. It means, within our own biology,
289
712260
3000
11:55
we have the yin and yang of morality.
290
715260
3000
11:58
We have oxytocin that connects us to others,
291
718260
2000
12:00
makes us feel what they feel.
292
720260
2000
12:02
And we have testosterone.
293
722260
2000
12:04
And men have 10 times the testosterone as women,
294
724260
2000
12:06
so men do this more than women --
295
726260
2000
12:08
we have testosterone that makes us want to punish
296
728260
3000
12:11
people who behave immorally.
297
731260
2000
12:13
We don't need God or government telling us what to do.
298
733260
2000
12:15
It's all inside of us.
299
735260
3000
12:18
So you may be wondering:
300
738260
2000
12:20
these are beautiful laboratory experiments,
301
740260
2000
12:22
do they really apply to real life?
302
742260
2000
12:24
Yeah, I've been worrying about that too.
303
744260
2000
12:26
So I've gone out of the lab
304
746260
2000
12:28
to see if this really holds in our daily lives.
305
748260
2000
12:30
So last summer, I attended a wedding in Southern England.
306
750260
3000
12:33
200 people in this beautiful Victorian mansion.
307
753260
3000
12:36
I didn't know a single person.
308
756260
2000
12:38
And I drove up in my rented Vauxhall.
309
758260
2000
12:40
And I took out a centrifuge and dry ice
310
760260
2000
12:42
and needles and tubes.
311
762260
2000
12:44
And I took blood from the bride and the groom
312
764260
2000
12:46
and the wedding party and the family and the friends
313
766260
2000
12:48
before and immediately after the vows.
314
768260
2000
12:50
(Laughter)
315
770260
2000
12:52
And guess what?
316
772260
2000
12:54
Weddings cause a release of oxytocin,
317
774260
2000
12:56
but they do so in a very particular way.
318
776260
3000
12:59
Who is the center of the wedding solar system?
319
779260
2000
13:01
The bride.
320
781260
2000
13:03
She had the biggest increase in oxytocin.
321
783260
2000
13:05
Who loves the wedding almost as much as the bride?
322
785260
3000
13:08
Her mother, that's right.
323
788260
2000
13:10
Her mother was number two.
324
790260
2000
13:12
Then the groom's father, then the groom,
325
792260
2000
13:14
then the family, then the friends --
326
794260
2000
13:16
arrayed around the bride
327
796260
2000
13:18
like planets around the Sun.
328
798260
2000
13:20
So I think it tells us that we've designed this ritual
329
800260
3000
13:23
to connect us to this new couple,
330
803260
2000
13:25
connect us emotionally.
331
805260
2000
13:27
Why? Because we need them to be successful at reproducing
332
807260
3000
13:30
to perpetuate the species.
333
810260
3000
13:33
I also worried that my trust experiments with small amounts of money
334
813260
3000
13:36
didn't really capture how often we actually trust our lives to strangers.
335
816260
4000
13:40
So even though I have a fear of heights,
336
820260
2000
13:42
I recently strapped myself to another human being
337
822260
2000
13:44
and stepped out of an airplane at 12,000 ft.
338
824260
3000
13:47
I took my blood before and after,
339
827260
2000
13:49
and I had a huge spike of oxytocin.
340
829260
3000
13:52
And there are so many ways we can connect to people.
341
832260
3000
13:55
For example, through social media.
342
835260
2000
13:57
Many people are Tweeting right now.
343
837260
2000
13:59
So we investigated the role of social media
344
839260
2000
14:01
and found the using social media
345
841260
2000
14:03
produced a solid double-digit increase in oxytocin.
346
843260
3000
14:06
So I ran this experiment recently for the Korean Broadcasting System.
347
846260
3000
14:09
And they had the reporters and their producers participate.
348
849260
4000
14:13
And one of these guys, he must have been 22,
349
853260
2000
14:15
he had 150 percent spike in oxytocin.
350
855260
3000
14:18
I mean, astounding; no one has this.
351
858260
2000
14:20
So he was using social media in private.
352
860260
2000
14:22
When I wrote my report to the Koreans,
353
862260
2000
14:24
I said, "Look, I don't know what this guy was doing,"
354
864260
2000
14:26
but my guess was interacting with his mother or his girlfriend.
355
866260
3000
14:29
They checked.
356
869260
2000
14:31
He was interacting on his girlfriend's Facebook page.
357
871260
2000
14:33
There you go. That's connection.
358
873260
3000
14:36
So there's tons of ways that we can connect to other people,
359
876260
3000
14:39
and it seems to be universal.
360
879260
2000
14:41
Two weeks ago,
361
881260
2000
14:43
I just got back from Papua New Guinea
362
883260
2000
14:45
where I went up to the highlands --
363
885260
2000
14:47
very isolated tribes of subsistence farmers
364
887260
3000
14:50
living as they have lived for millenia.
365
890260
3000
14:53
There are 800 different languages in the highlands.
366
893260
3000
14:56
These are the most primitive people in the world.
367
896260
3000
14:59
And they indeed also release oxytocin.
368
899260
3000
15:02
So oxytocin connects us to other people.
369
902260
4000
15:06
Oxytocin makes us feel what other people feel.
370
906260
2000
15:08
And it's so easy to cause people's brains
371
908260
3000
15:11
to release oxytocin.
372
911260
2000
15:13
I know how to do it,
373
913260
2000
15:15
and my favorite way to do it is, in fact, the easiest.
374
915260
2000
15:17
Let me show it to you.
375
917260
2000
15:24
Come here. Give me a hug.
376
924260
2000
15:26
(Laughter)
377
926260
2000
15:28
There you go.
378
928260
2000
15:30
(Applause)
379
930260
9000
15:39
So my penchant for hugging other people
380
939260
2000
15:41
has earned me the nickname Dr. Love.
381
941260
2000
15:43
I'm happy to share a little more love in the world,
382
943260
2000
15:45
it's great,
383
945260
2000
15:47
but here's your prescription from Dr. Love:
384
947260
2000
15:49
eight hugs a day.
385
949260
3000
15:52
We have found that people who release more oxytocin
386
952260
2000
15:54
are happier.
387
954260
2000
15:56
And they're happier
388
956260
2000
15:58
because they have better relationships of all types.
389
958260
3000
16:01
Dr. Love says eight hugs a day.
390
961260
3000
16:04
Eight hugs a day -- you'll be happier
391
964260
2000
16:06
and the world will be a better place.
392
966260
2000
16:08
Of course, if you don't like to touch people, I can always shove this up your nose.
393
968260
3000
16:11
(Laughter)
394
971260
2000
16:13
Thank you.
395
973260
2000
16:15
(Applause)
396
975260
13000
About this website

This site will introduce you to YouTube videos that are useful for learning English. You will see English lessons taught by top-notch teachers from around the world. Double-click on the English subtitles displayed on each video page to play the video from there. The subtitles scroll in sync with the video playback. If you have any comments or requests, please contact us using this contact form.

https://forms.gle/WvT1wiN1qDtmnspy7