Competitiveness, aggression and hormone levels: How they are connected

Participants in a laboratory study were required to master competitive tasks over ten rounds. They competed against each other either as individuals or as teams, whereby one side lost the competition and the other side won. Participants were allowed to give full rein to their aggressive impulses during the competition. For this purpose, at the beginning of each round, they were asked to specify how loud an unpleasant noise would be that the opponent would be required to listen to through headphones if they lost the round. Saliva samples were collected from the participants prior to and after the competition in order to document changes to hormone levels.

Prof. Dr. Oliver Schultheiss and Dr. Jonathan Oxford from the Chair of General Psychology II at FAU found that men tended to behave more aggressively than women, that losers were more aggressive than winners and that teams were more aggressive than individuals. Furthermore, the researchers also detected a correlation between aggression and levels of the stress hormone cortisol; the more aggressively a person behaved, the lower their cortisol level was. "Our results show that the usual suspects are the ones who become aggressive -- namely participants who are male and frustrated. But our analysis also revealed that it was easier for participants who were part of a team to attack others than it was for individuals. At the same time, elevation of stress hormones when encountering a threat that cannot be mastered is in actual fact associated with less aggression," explains Schultheiss.

The researchers placed a particular emphasis on the female subjects. They discovered that the hormonal reaction to victory or defeat that occurred in women or female teams was significantly dependent on their personal thirst for power. Women with a particularly marked thirst for power had higher levels of the sex hormones testosterone and estradiol after a victory than after a defeat. This reaction was not recorded in women who a less pronounced power-orientated outlook. This hormonal reaction is the reason why dominant behaviour in women is intensified by a victory and subdued by a defeat.