The study, published in Psychological Science, found people prefer potentially useful emotions, even if unpleasant.

Psychologists Maya Tamir and Christopher Mitchell of Boston College and James Gross of Stanford University told study participants they would be playing a computer game called "Soldier of Fortune" in which killing enemies is the goal. The researchers found that participants preferred activities that were likely to make them angry -- e.g., listening to anger-inducing music or recalling past events in which they were angry -- when they expected to perform the confrontational task.

In contrast, participants preferred more pleasant activities when they expected to play a non-confrontational game.

With this preference established, the participants were randomly assigned either to the angry or excited emotion condition or to a neutral condition.

The angry participants performed better than the others in playing the confrontational game by "successfully killing more enemies." However, angry participants did not perform better than others in the non-confrontational game.