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."