Prejudice and truth about the effect of testosterone on human bargaining behaviour

• Published in: Nature (London) Vol. 463; no. 7279; pp. 356 - 359
• Main Authors: Eisenegger, C., Naef, M., Snozzi, R., Heinrichs, M., Fehr, E.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 21.01.2010; Nature Publishing Group
• Subjects: Administration, Sublingual; Adult; Aggression - drug effects; Aggression - physiology; Aggression - psychology; Aggressive behavior; Analysis; Bargaining; Behavior; Behavioral psychophysiology; Biological and medical sciences; Conspecifics; Cooperative Behavior; Double-Blind Method; Female; Fundamental and applied biological sciences. Psychology; Game Theory; Hormones and behavior; Human acts; Human behavior; Humanities and Social Sciences; Humans; letter; Models, Biological; multidisciplinary; Physiological aspects; Placebos; Prejudice; Psychology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Reproducibility of Results; Robbery; Science; Science (multidisciplinary); Social aspects; Social Behavior; Social behavior in animals; Social Class; Social interaction; Testosterone; Testosterone - administration & dosage; Testosterone - pharmacology; Germany; Human; Testosterone; Androgen; Social interaction; Bargaining; Testicular hormone; Sex steroid hormone; Experimental study; Woman; Interpersonal relation
• ISSN: 0028-0836; 1476-4687; 1476-4687
• DOI: 10.1038/nature08711

Perception-fuelled behaviour Hormones are known to modulate social interactions between animals, with testosterone classically thought to induce aggressive behaviour. Although this categorization has been extrapolated to humans — hence the familiar concept of 'testosterone-fuelled' behaviour — it is unclear whether testosterone does in fact promote antisocial actions. In a bargaining game, a single dose of testosterone was found to increase fair behaviour, reduce conflict and enhance social interactions. But those subjects who were led to believe that they had received testosterone, whether or not they actually had, behaved more unfairly than those who thought they had received placebo, again whether or not they actually did. Thus the negative, antisocial connotation of increasing testosterone seems strong enough to induce negative social behaviour even when the biological result is actually the opposite. Evidence from animal studies shows that testosterone can induce aggressive behaviour, but whether this extrapolates to humans is an area of debate. The sublingual administration of a single dose of testosterone in women is now shown to cause a substantial increase in fair bargaining behaviour, although subjects who believed they received testosterone behaved much more unfairly than those who thought they received a placebo. Both biosociological and psychological models, as well as animal research, suggest that testosterone has a key role in social interactions 1 , 2 , 3 , 4 , 5 , 6 , 7 . Evidence from animal studies in rodents shows that testosterone causes aggressive behaviour towards conspecifics 7 . Folk wisdom generalizes and adapts these findings to humans, suggesting that testosterone induces antisocial, egoistic, or even aggressive human behaviours. However, many researchers have questioned this folk hypothesis 1 , 2 , 3 , 4 , 5 , 6 , arguing that testosterone is primarily involved in status-related behaviours in challenging social interactions, but causal evidence that discriminates between these views is sparse. Here we show that the sublingual administration of a single dose of testosterone in women causes a substantial increase in fair bargaining behaviour, thereby reducing bargaining conflicts and increasing the efficiency of social interactions. However, subjects who believed that they received testosterone—regardless of whether they actually received it or not—behaved much more unfairly than those who believed that they were treated with placebo. Thus, the folk hypothesis seems to generate a strong negative association between subjects’ beliefs and the fairness of their offers, even though testosterone administration actually causes a substantial increase in the frequency of fair bargaining offers in our experiment.