antennae. But it may surprise you to know that there are some situations in

which psychopaths are actually more adept at saving lives than they are at taking them.

So let me give you an example of what I mean by that, okay?  Imagine you’ve got a train

and it’s hurtling down a track.  In its path, five people are trapped on the line

and cannot escape. Fortunately, you can flick a switch, which

diverts the train down a fork in that track, away from those five people, but at a price. There

is another person trapped down that fork and the train will kill them instead. Question:

 Should you flick the switch?

Now, most people have little trouble deciding what to do under those

circumstances; though, the thought of flicking the switch isn’t

exactly a nice one, the utilitarian choice as it were, killing just

the one person instead of the five represents the least worst option,

okay.

But now let me give you a variation. You’ve got a

train speeding out of control down a track and it’s gonna plow into

five people on the line.  But this time you are standing behind a very

large stranger on a footbridge above that track. The only way

to save the people is to heave the stranger over.  He will fall to a

certain death, but his considerable bulk will block the train, saving

five lives.  Question.  Should you flick the switch?

Now we’ve got what we might call a real dilemma on our

hands, okay.  While the score in lives is precisely the same as in the

first scenario, five to one, one’s choice of action appears far

trickier.  Now why should that be?  Well, the reason it turns out, all

boils down to temperature, okay?

Case one represents what we might call an impersonal

dilemma.  It involved those areas of the brain, the prefrontal cortex,

the posterior parietal cortex, in particular, the anterior para

singular cortex, the temporal pole and the superior temporal sulcus -

bit of neuroanatomy for you there - primarily responsible for what we

call cold empathy, for reasoning and rational thought.

Case two, on the other hand, represents what we might

call a personal dilemma.  It involves the emotion center of the brain

known as the amygdala, the circuitry of hot empathy.  What we might

call the feeling of feeling what another person is feeling.

Now, psychopaths, just like most normal members of the

population, have no trouble at all with case one.  They flick the

switch and the train   diverts accordingly.  Killing just the one person

instead of the five.  But, this is where the plot thickens.  Quite

unlike normal members of the population, psychopaths also experience

little difficulty with case two.

Psychopaths, without a moment’s hesitation are perfectly

willing to chuck the fat guy over the rails, if that’s what the doctor

orders.  Now moreover, this difference in behavior has a distinct

neural signature.  The pattern of brain activation in both normal

people and psychopaths is identical on the presentation of the

impersonal moral dilemma, but radically different when things start to

get a bit more personal.

Imagine that I were to hook you up to a brain scanner, a

functional magnetic resonance imaging machine, and were to present

you with those two dilemmas, okay.  What would I observe as you went about

trying to solve them?  Well, at the precise moment that the nature of

the dilemma switches from impersonal to personal, I would see the

emotion center of your brain, your amygdala and related brain

circuits, the medial orbital frontal cortex for example, light up like

a pinball machine.  I would witness the moment in other words when

emotion puts it money in the slot.

But in psychopaths, I would see precisely nothing.  And

the passage from impersonal to personal would slip by unnoticed.

Because that emotion neighborhood of their brains, that emotional zip

code has a neural curfew.  And that’s why they’re perfectly happy to

chuck that fat guy over the side without even batting an eye.

Directed / Produced by Jonathan Fowler & Elizabeth Rodd