Passage 6 Generosity is Natural for Kind-Hearted People
慷慨是一种天性 《新科学家》

[00:01]Getting into the spirit of giving during the holiday season
[00:05]may seem like a struggle, but it turns out generous people
[00:10]aren't fighting the urge to oppress others, as some have suggested.
[00:15]Instead, generosity - or the desire for fairness seems automatic
[00:21]and arises from activation in a brain area that controls intuition and emotion.
[00:29]Neuropsychologists defined "prosocial" people
[00:34]as those who prefer to share and share alike,
[00:38]and "individualists" as those who are primarily concerned
[00:42]with maximising their own gain.
[00:45]According to one theory, the difference between these two groups
[00:50]is that prosocial people actively suppress their selfish tendencies
[00:56]with the help of their prefrontal cortex.
[01:00]But Masahiko Haruno of Tamagawa University in Tokyo wondered
[01:07]if some people might instead have an automatic dislike to inequality.
[01:14]Haruno, along with Christopher Frith of University College London
[01:20]used functional MRI to scan the brains of 25 prosocial people
[01:26]and 14 individualists
[01:29]while they estimated their preference for a series of money distributions
[01:35]between themselves and a hypothetical other person.
[01:39]As expected, the prosocial group preferred even splits
[01:44]while the individualists favoured distributions where they got the most money.
[01:50]A less predictable finding was that the only brain region
[01:55]that differed in activity between the two groups was the amygdala.
[02:01]When presented with unfair money distributions the activity
[02:05]in the amygdala increased significantly in prosocial people
[02:10]but not in the individualists. "And the more they disliked the split,
[02:15]the more activity you saw in this region," says Frith.
[02:20]"The amygdala tends to respond automatically, without thought,
[02:26]or even without awareness," says Frith. Combined with the fact
[02:32]that there was no difference in activity in the prefrontal cortex
[02:37]responsible for suppressing urges this suggested
[02:42]that the suppression theory might not be borne out.
[02:47]To further test if the prosocial dislike to unfairness was automatic,
[02:53]the researchers repeated the test,
[02:56]this time giving the participants a memory task to complete at the same time
[03:02]as they estimated splits.
[03:05]They found that the prosocials' brains
[03:08]still reacted to the unfair distributions,
[03:12]even when the parts of their brain responsible for deliberative processes
[03:17]were taken up by other tasks,
[03:20]suggesting they were not suppressing selfish desires.
[03:24]Carolyn Declerck, a neuroeconomist at the University of Antwerp, Belgium,
[03:31]says the results fit with her own, as yet unpublished,
[03:36]data showing that prosocials seem to be driven by
[03:41]an automatic sense of morality.
[03:44]"So far, all our behavioural and MRI experiments confirm
[03:50]that prosocials are intrinsically motivated to cooperate," she says.
[03:57]Haruno will next try to figure out
[04:01]how this difference in the activity of the amygdala arises.
[04:06]It's partly genetic, but also likely influenced by a person's environment,
[04:12]he says, particularly the social interactions during childhood.
[04:19]He says it is interesting to think there might be ways to
[04:23]promote this activity to "realise a more prosocial society."