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Egoistic behavior through testosterone

Testosterone impairs interpersonal cooperation

01.02.2012

The male sex hormone testosterone leaves women more selfish and less cooperative, British researchers at University College London report on the portal „Proceedings of the Royal Society B“.

Researchers led by Nicholas D. Wright from the Institute of Neurology at University College London have found in their recent research that elevated levels of testosterone reduce women's co-operative behavior and make them more selfish. For the first time, a hormone was discovered that causes restrictions on interpersonal cooperation.

Effects of hormones on social behavior
While it has long been known that some hormones such as oxytocin the „promote cooperative behavior in economic tasks“, The British researchers went in search of a hormone with opposite effect. To this end, Nicholas D. Wright and colleagues investigated the effects of the hormone testosterone on women's behavior. A couple of two women each was placed in front of a computer monitor and was to determine in two consecutive images of one on which a sought-after motif hid. If both women chose the same picture, the next pictures followed. If the study participants opted for different images, the researchers invited them to discuss and agree on a mutually acceptable decision. The same experiment the women went through twice within a week's interval. In one of the tests, women were given a placebo supplement and the other was given a dose of testosterone. It showed a surprising effect of the male sex hormone on the cooperative decision-making.

Testosterone excess worsens cooperative decision-making
For example, when evaluating the test results, the researchers found that women without the use of testosterone were able to significantly improve their overall results through cooperative decisions. The hit rate in cooperation was significantly higher than in the women who had previously taken a testosterone preparation, the British researchers report in their latest release. The women with elevated testosterone levels behaved according to the scientists much less cooperative and far more often insisted on their own opinion. This resulted in a much lower overall team hit rate, study director Nicholas D. Wright said. According to the researchers, an excess of testosterone leads to a „disturbed collaborative decision-making“, which brings a significant reduction in the performance advantage of the cooperation. The „individual decision-making ability“ remained however with changed Testosteronspiegel „unaffected“, Wright and colleagues continue.

Interplay of biological factors determines interpersonal cooperation
According to the British researchers, social behavior is determined by a finely tuned interplay of biological factors. Here, cooperation in social constellations is indispensable, since this helps to take into account the abilities but also the respective level of knowledge of individual persons and in this way enables or improves the decision-making in groups. Cooperation forms the basis for a kind of collective intelligence. However, under certain circumstances such cooperation may also result in worse benefits or decisions, which is why „a balance is made between a cooperative and an egocentric disposition“ must, the British researchers write in the „Proceedings B“. At this point, testosterone acts as a weight in the direction of egocentric disposition, which also improves cooperative decision-making under normal circumstances.

However, if the level of testosterone is excessive, this will have a significant negative impact on cooperative decision-making. Other opinions are ignored and in case of doubt, the most dominant person prevails with their position - regardless of whether it comes to a correct or wrong assessment. In the case of impaired testosterone levels of individual group members, the British researchers therefore assume that the collective decision-making process is significantly impaired. (Fp)