writes "According to a recent study by a psychology study at the University of Michigan, a fleeting look of anger is actually a reward for people with high testosterone levels. In the study, they first measured testosterone levels of the participants, then had the participants perform a "learning task" in which complex key sequences were followed by either an angry face, a neutral face, or no face at all. Participants with high testosterone levels compared to the group learned the key sequence with the angry face faster than the other sequences, while participants with moderate or lower testosterone did not. The effect emerged even more strongly when the angry faces were presented subliminally (i.e., too fast for conscious identification). According to Michelle Wirth, lead author of the study, "Better learning of a task associated with anger faces indicates that the anger faces were rewarding, as in a rat that learns to press a lever in order to receive a tasty treat. In that sense, anger faces seemed to be rewarding for high-testosterone people, but aversive for low-testosterone people.""