From Science:
Testosterone has a reputation for causing violent and antisocial behavior. But that's a bad rap, according to a new study. Women given the hormone acted more fairly in an economic game than did those given a placebo. Interestingly, however, women in the placebo group were more antisocial if they thought they had received testosterone, indicating that our negative attitudes toward the hormone have a powerful sway on behavior. Scientists led by Ernst Fehr, a professor of neuroeconomics at the University of Zurich in Switzerland, suspected that testosterone is really about gaining and maintaining social status. And although status concerns lead to aggression, they theorized that testosterone does not necessarily make a person more self-seeking.
The team tested this idea by recruiting 121 women in their 20s to play a game that tests fairness. Two players, A and B, have to agree on the division of 10 money units, in this case Swiss francs. A proposes a division; B can only accept or reject. If B rejects the offer, neither gets any money. All the women were given a dose of either testosterone or a placebo under the tongue. Then 60 women designated as A played the game three times with three different partners, communicating through a computer. A “fair” offer would be a 50-50 split. So, according to common wisdom, A would make more unfair offers if she were high on testosterone. The status hypothesis predicts the opposite: An unfair offer is more likely to evoke a rejection, which is an affront to A's status. So A is more likely to make an offer that B will accept.
The status hypothesis won. The women given the testosterone made significantly higher offers on average, the group reports online today in Nature: 3.9 francs versus 3.4 francs for the placebo group. “Our interpretation of this finding is that testosterone renders concerns for social status more prominent,” says Fehr.
More here.