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Begin forwarded message:

Hi guys,

this is so exciting!  attached is the paper, the news and views, and

the press release.  even though they didnt use our image for the

cover, we are one of the 4 cover-featured articles!  Nature's press

release is pasted below here.  Also, here are links to some

particularly good media attention:

All things considered:

Nature podcast:

Blogs/newspapers:

Nature press release:

Winners in games of cooperation are much less likely to inflict

punishments on others, according to a new study of social

interactions. The discovery casts doubt on the commonly held view that

costly punishment between peers has evolved, because everyone tends to

benefit on average, despite conferring a cost to those doing the

punishing.

            Instead, suggest researchers led by Martin Nowak of

Harvard University, costly punishments may have evolved not for the

greater good, but for other reasons, such as to exert power over

others and to establish dominance hierarchies.

            Nowak and his team asked volunteers to play an extended

version of the classic 'prisoner's dilemma' game, in which

participants could choose between cooperation, defection and costly

punishment.

            The most successful players, who finished with the highest

overall totals, tended not to punish others, whereas those with lowest

final totals had punished most often, the researchers in this week's

Nature report. Winners use tit-for-tat like strategies, while losers

escalate in costly punishment which leads to downward spirals of

retaliation. This suggests that costly punishment (or strong

reciprocity) may not be as advantageous as previous researchers have

proposed. "Winners don't punish", the researchers say, "whereas losers

punish and perish".