Abigail (Abby) Marsh

So generating an internal representation of that state that helps you then recognize it in others.

And what we hypothesized at the beginning of our research with altruistic people is that if very uncaring people seem to be unusually insensitive to other people's distress, and that is underpinned by deficits in a structure called the amygdala, both in its reduced activation in response to other people's distress and its lower volume.

So people who are psychopathic have amygdalas that are unusually small on average.

Maybe people who are unusually caring and highly altruistic will look exactly the opposite.

They'll be sensitive to other people's distress, better recognizing it, and we would see increased amygdala activation in response to that distress and maybe larger amygdalas as well.

So those are our hypotheses setting out.

That was exactly what we found.

The altruistic people that we tested on our very first study looked the opposite of people who were psychopathic.

They were relatively better at recognizing other people's fear.

And they were not better at recognizing other expressions.

So we also tested how well they recognized anger.

And they didn't recognize anger better.

In fact, they recognized it a little worse.

But they were very specifically sensitive to other people's distress.

And we also found that in our brain scanning studies, their amygdala showed more activation in response to images of other people's fear.

Whereas again, it did not show that response to other people's anger.

And finally, their amygdalas were on average about 8% larger than in a comparable group of adults that we also tested who were not altruistic kidney donors.

So social discounting reflects how you value other people's outcomes as a function of their social distance from you.

Basically, how much are you willing to sacrifice to benefit another person?

And most people in standard social discounting tasks are very willing to sacrifice to benefit people close to them, but their willingness to sacrifice drops dramatically, hyperbolically, as people become more socially distant.