0:00:18.209,0:00:23.710
These two Nazi scientists worked[br]at the Dachau Concentration Camp

0:00:23.729,0:00:25.459
during World War II.

0:00:26.250,0:00:29.250
They were conducting an experiment

0:00:29.292,0:00:33.667
to see how long a human being[br]could survive in freezing water.

0:00:35.542,0:00:37.168
Like good scientists,

0:00:37.250,0:00:43.834
they took systematic measures[br]including duration until death.

0:00:45.834,0:00:49.876
Examples of human cruelty[br]of this kind raise a big question.

0:00:50.501,0:00:54.793
How is it possible[br]to treat a person as a mere object?

0:00:56.918,0:01:03.210
The traditional explanation[br]for human cruelty is in terms of evil.

0:01:04.167,0:01:09.376
I find the concept of evil[br]unhelpful and unscientific.

0:01:09.918,0:01:13.918
It implies that the person is possessed[br]by some supernatural force.

0:01:14.709,0:01:18.293
Even worse it's dangerously circular;

0:01:18.334,0:01:22.293
if the definition of evil[br]is the absence of good,

0:01:22.334,0:01:24.208
then all we're really saying

0:01:24.209,0:01:27.541
is he did something bad[br]because he is not good.

0:01:27.542,0:01:30.917
It hasn't really taken us[br]any further forward.

0:01:31.959,0:01:35.251
In contrast the concept of empathy,

0:01:35.292,0:01:38.666
I'm going to argue[br]is scientifically helpful;

0:01:38.667,0:01:41.792
you can measure it, you can study it.

0:01:42.375,0:01:48.458
Empathy has two distinct components --[br]cognitive and affective.

0:01:49.667,0:01:52.209
Cognitive empathy is the ability

0:01:52.250,0:01:55.001
to imagine someone else's[br]thoughts and feelings;

0:01:55.042,0:01:57.668
putting yourself into[br]someone else's shoes.

0:01:57.684,0:01:59.384
It's the recognition part.

0:02:00.584,0:02:05.751
Affective empathy is the drive to respond[br]with an appropriate emotion

0:02:05.751,0:02:08.252
to what someone else[br]is thinking or feeling.

0:02:08.959,0:02:12.959
I'm going to argue[br]that low affective empathy

0:02:13.000,0:02:17.000
is a necessary factor[br]to explain human cruelty.

0:02:18.209,0:02:21.958
Empathy isn't all or none;[br]it comes by degrees,

0:02:21.959,0:02:25.001
and there a individual differences in it.

0:02:25.042,0:02:28.751
So it gives rise[br]to the empathy bell curve.

0:02:28.792,0:02:31.875
Most of us are in the middle[br]of this spectrum

0:02:31.921,0:02:34.571
with average amounts of empathy.

0:02:34.584,0:02:38.918
There are some people[br]who have above average levels of empathy.

0:02:39.114,0:02:40.494
But what are the factors

0:02:40.501,0:02:44.501
that can lead an individual[br]to have low empathy

0:02:45.125,0:02:48.500
either temporarily or permanently?

0:02:48.542,0:02:52.542
What are those social factors?[br]What are those biological factors?

0:02:55.417,0:02:59.251
One social factor[br]is obedience to authority.

0:03:00.209,0:03:04.750
The experiment by Stanley Milgram[br]at Yale University showed

0:03:04.751,0:03:08.874
that people are willing to administer[br]electric shocks to someone

0:03:08.874,0:03:10.334
to help them learn,

0:03:10.335,0:03:13.584
if they're instructed to do so[br]by an authority figure.

0:03:14.262,0:03:16.035
This suggests that simply,

0:03:16.035,0:03:20.334
following orders may be one factor[br]that can erode our empathy.

0:03:22.209,0:03:25.292
A second social factor is ideology.

0:03:26.542,0:03:31.834
When the terrorists flew the planes[br]into the World Trade Center on 9/11,

0:03:32.426,0:03:34.006
We have to assume

0:03:34.026,0:03:36.916
that they were in the grip[br]of a strongly-held belief

0:03:36.918,0:03:38.794
that they were doing the right thing.

0:03:40.876,0:03:42.500
Of course, we don't know

0:03:42.501,0:03:45.210
whether the terrorists[br]who signed up for that action

0:03:45.233,0:03:47.513
had low empathy to begin with,

0:03:48.210,0:03:49.575
but it's possible

0:03:49.575,0:03:52.859
that their ideological beliefs[br]were another factor

0:03:52.859,0:03:56.519
that could erode[br]their empathy for their victims.

0:03:57.459,0:04:01.960
A third social factor [br]is in-group/out-group relations.

0:04:02.753,0:04:07.463
In Rwanda, we saw one ethnic group[br]used propaganda

0:04:07.493,0:04:09.584
to stereotype the out-group;

0:04:09.616,0:04:13.966
describing them as subhuman[br]and as cockroaches.

0:04:14.784,0:04:17.734
When we dehumanize a group as the enemy,

0:04:18.533,0:04:22.743
we have the potential to lose our empathy;

0:04:23.600,0:04:25.820
and we saw the catastrophic genocide

0:04:25.831,0:04:27.141
that ensued.

0:04:29.317,0:04:33.317
But none of these social factors[br]can explain individuals like Ted Bundy.

0:04:34.706,0:04:38.086
He started his adult career[br]as a psychology student

0:04:38.114,0:04:40.084
of the University of Washington

0:04:40.111,0:04:43.021
where he volunteered[br]on a telephone helpline

0:04:43.033,0:04:46.553
and persuaded women to meet him.

0:04:46.569,0:04:48.829
And over the successive years,

0:04:48.834,0:04:54.084
he committed rape and murder[br]of at least 30 women.

0:04:55.159,0:04:58.369
We can assume that he had[br]good cognitive empathy

0:04:58.398,0:05:01.878
because he was able [br]to deceive his victims,

0:05:02.384,0:05:07.384
but that he lacked affective empathy[br]- he just didn't care -

0:05:07.456,0:05:10.456
and he lacked it in enduring ways.

0:05:12.203,0:05:17.303
The evidence that psychopaths[br]like Ted Bundy lack affective empathy

0:05:17.325,0:05:20.203
comes from an experiment by James Blair

0:05:20.209,0:05:22.793
that was conducted in Broadmoor Hospital.

0:05:22.829,0:05:25.899
He showed psychopaths and a control group

0:05:25.928,0:05:28.228
three different types of images,

0:05:28.248,0:05:34.238
threatening images, neutral images,[br]and images of people in distress.

0:05:34.980,0:05:37.240
What he found was that the psychopaths

0:05:37.260,0:05:41.435
only showed reduced physiological response

0:05:41.435,0:05:44.445
when they saw the images[br]of people in distress.

0:05:44.467,0:05:48.467
So this suggests that they lacked[br]affective empathy.

0:05:50.035,0:05:54.755
People with autism have difficulties[br]with cognitive empathy.

0:05:54.770,0:05:57.880
They struggle to imagine[br]other people's thoughts,

0:05:57.900,0:06:01.870
their motives, their intentions,[br]and their feelings.

0:06:01.873,0:06:05.553
But people with autism[br]don't tend to hurt other people;

0:06:05.569,0:06:08.059
instead, they are confused by other people

0:06:08.073,0:06:12.833
and withdraw socially, preferring[br]the more predictable world of objects.

0:06:13.845,0:06:17.394
People with autism[br]have intact affective empathy

0:06:17.394,0:06:19.864
because when they hear[br]that somebody is suffering

0:06:19.864,0:06:21.769
it upsets them.

0:06:22.937,0:06:25.097
This leads us to imagine

0:06:25.122,0:06:29.712
that people with autism[br]and psychopaths are mirror opposites.

0:06:30.198,0:06:34.198
The psychopath has good cognitive empathy[br]- that's how they can deceive -

0:06:34.967,0:06:37.627
but they have reduced affective empathy.

0:06:37.726,0:06:41.256
People with autism[br]have intact affective empathy,

0:06:41.278,0:06:45.278
but struggle with cognitive empathy[br]for neurological reasons.

0:06:48.062,0:06:50.462
Psychopaths don't come out of nowhere.

0:06:50.494,0:06:52.084
Many of them have shown

0:06:52.124,0:06:55.774
antisocial behavior [br]and delinquency in their teens.

0:06:56.375,0:07:01.126
John Bowlby at the Tavistock Clinic[br]in London studied delinquents and found

0:07:01.142,0:07:06.212
that many of them had experienced[br]emotional neglect in early childhood.

0:07:07.248,0:07:11.808
He argued that the absence[br]of parental love in early childhood

0:07:11.816,0:07:14.836
is another factor[br]that can erode your empathy.

0:07:17.338,0:07:20.448
But we know that early experience[br]can't be the whole story

0:07:20.469,0:07:23.579
because not everyone[br]who has a bad childhood

0:07:23.595,0:07:25.275
loses their empathy.

0:07:25.792,0:07:31.001
Avshalom Caspi at the Institute[br]of Psychiatry in London showed

0:07:31.032,0:07:35.553
that if you've experienced[br]severe maltreatment in childhood

0:07:36.017,0:07:38.947
that increases your risk of delinquency.

0:07:39.542,0:07:42.709
But your risk of deliquency[br]goes up even more

0:07:42.742,0:07:47.162
if you also a carrier[br]of one version of the MAO-A gene

0:07:47.763,0:07:49.263
shown here in red;

0:07:49.763,0:07:52.463
so genes and environment interact.

0:07:54.441,0:07:56.601
Another biological factor

0:07:56.628,0:08:01.738
that is associated with empathy levels[br]is the hormone testosterone.

0:08:02.665,0:08:06.405
In the fetus, testosterone[br]shapes brain development.

0:08:06.905,0:08:08.654
We've measured testosterone

0:08:08.684,0:08:11.815
in the amniotic fluid[br]that surrounds the baby

0:08:11.815,0:08:15.945
in women who are having [br]amniocentesis during pregnancy.

0:08:17.074,0:08:21.964
We then wait for the baby to be born,[br]and we follow up the children.

0:08:22.868,0:08:25.728
When the children were eight years old,

0:08:25.748,0:08:28.418
we asked them which word best describes

0:08:28.448,0:08:31.618
what the person in the photo[br]is thinking or feeling.

0:08:32.188,0:08:35.467
Here the correct answer is[br]he is interested in something.

0:08:36.020,0:08:41.191
What we found was that the higher[br]the level of fetal testosterone,

0:08:41.207,0:08:44.668
the more difficulties the child was having

0:08:45.124,0:08:47.604
at this test of cognitive empathy.

0:08:48.446,0:08:53.846
How much empathy we show[br]is a function of the empathy circuit;

0:08:53.861,0:08:56.421
a network of regions in the brain.

0:08:57.070,0:08:59.190
Here we can look at just two of them:

0:08:59.209,0:09:04.220
in red, for left ventromedial[br]prefrontal cortex,

0:09:04.667,0:09:06.667
and in blue, the amygdala.

0:09:08.260,0:09:10.940
This is Phineas Gage [br]who suffered damage

0:09:10.940,0:09:14.644
to his left ventromedial prefrontal cortex

0:09:14.644,0:09:20.271
after dynamite blasted a metal rod[br]up behind his eye and through his brain.

0:09:21.028,0:09:25.308
Before the accident, he was described[br]as a polite, considerate individual.

0:09:26.080,0:09:29.190
After the accident,[br]he was described as rude

0:09:29.210,0:09:30.897
and no longer able to judge

0:09:30.907,0:09:34.087
what was socially appropriate[br]for different situations.

0:09:34.109,0:09:36.479
He'd lost his cognitive empathy.

0:09:39.125,0:09:43.528
Jean Decety at the University of Chicago[br]used brain scanning

0:09:43.578,0:09:45.859
- functional magnetic resonance imaging -

0:09:46.505,0:09:49.075
to look at the teenage delinquent brain

0:09:49.099,0:09:53.879
whilst they were watching films[br]where somebody experiences pain

0:09:53.899,0:09:59.250
such as when this piano player's fingers[br]got crushed by the lid of the piano

0:09:59.266,0:10:01.436
falling down on his fingers.

0:10:01.471,0:10:05.981
What he found was that teenagers[br]with delinquency didn't show

0:10:06.011,0:10:09.141
the typical levels of activity[br]in the amygdala --

0:10:09.152,0:10:12.382
part of the empathy circuit in the brain.

0:10:12.411,0:10:15.921
But let's not forget[br]the positive side of empathy.

0:10:16.420,0:10:19.140
Most of us have enough empathy,

0:10:19.155,0:10:22.595
and some people[br]have high levels of empathy.

0:10:23.547,0:10:26.907
When these two men formed a relationship

0:10:26.938,0:10:30.408
based on mutual respect and on empathy,

0:10:30.433,0:10:33.723
it let to the end of apartheid[br]in South Africa.

0:10:34.859,0:10:38.499
Empathy is vital for a healthy democracy;

0:10:39.077,0:10:41.797
it ensures that we listen[br]to different perspectives,

0:10:42.446,0:10:46.836
we hear other people's emotions,[br]and we also feel them.

0:10:47.527,0:10:51.527
Indeed without empathy,[br]democracy would not be possible.

0:10:54.292,0:10:56.842
I met this two women[br]in Cambridge this week

0:10:56.865,0:10:58.315
when they came to visit.

0:10:59.292,0:11:03.292
On the left is Siham,[br]and she is a Palestinian woman;

0:11:04.023,0:11:08.183
her brother was shot[br]and killed by an Israeli bullet.

0:11:10.000,0:11:14.501
On the right is Robi;[br]she is an Israeli woman.

0:11:15.013,0:11:18.303
Her son was killed[br]by a Palestinian bullet.

0:11:19.730,0:11:23.030
These two women[br]have taken the courageous step

0:11:23.030,0:11:26.694
of forming a relationship[br]across the political divide.

0:11:27.529,0:11:30.669
They haven't given in[br]to the emotion of revenge

0:11:31.008,0:11:34.078
which would simply perpetuate[br]the cycle of violence.

0:11:34.434,0:11:38.524
Instead, they've used their empathy[br]to recognize that they both share

0:11:38.550,0:11:44.280
the same sorrow, the same awful pain[br]of having lost a loved one.

0:11:46.788,0:11:52.948
Empathy is our most valuable[br]natural resource for conflict resolution.

0:11:54.167,0:11:57.209
We could wait for our political leaders

0:11:57.237,0:12:00.247
to use empathy[br]- and that would be refreshing -

0:12:00.274,0:12:03.536
but actually, [br]we could all use our empathy.

0:12:03.542,0:12:06.535
As Siham and Robi told me,

0:12:06.536,0:12:10.226
"The conflict won't stop[br]until we empathize."

0:12:10.265,0:12:11.545
Thank you.

0:12:11.571,0:12:13.301
(Applause)