Testosterone administration does not affect men's rejections of low ultimatum game offers or aggressive mood

Abstract

Correlative evidence suggests that testosterone promotes dominance and aggression. However, causal evidence is scarce and offers mixed results. To investigate this relationship, we administered testosterone for 48h to 41 healthy young adult men in a within-subjects, double-blind placebo-controlled balanced crossover design. Subjects played the role of responders in an ultimatum game, where rejecting a low offer is costly, but serves to destroy the proposer's profit. Such action can hence be interpreted as non-physical aggression in response to social provocation. In addition, subjects completed a self-assessed mood questionnaire. As expected, self-reported aggressiveness was a key predictor of ultimatum game rejections. However, while testosterone affected subjective ratings of feeling energetic and interested, our evidence strongly suggests that testosterone had no effect on ultimatum game rejections or on aggressive mood. Our findings illustrate the importance of using causal interventions to assess correlative evidence.

Testosterone promotes either dominance or submissiveness in the Ultimatum Game depending on players’ social rank

“…The prediction that high testosterone would promote the rejection of unfair offers, based on the findings of earlier studies 11, 15 , was not confirmed. However, our results are in line with those of other studies that reported no effect of testosterone on rejection in the UG 16, 17, 19 . We found a strong main effect of testosterone on offer level, which is consistent with Eisenegger et al .…”

“…This finding was replicated by Mehta and Beer 15 both in men and women, but other studies have reported no statistically significant effect of exogenous testosterone on the rejection of inequitable offers 16–19 .…”

“…18 , as we report similar behaviour among senior players but not among junior players, suggesting that exogenous testosterone may have different effects on players who are unknown to one another, compared to players who are embedded in a pre-existing status hierarchy. The causal relationship between testosterone and behaviour can also only be elucidated by experimental studies in which testosterone is directly manipulated 16 . Although studying exogenous testosterone effects may elucidate the causal relationships, there is also an opportunity for further development of the methodology.…”

“…The inconsistent effects of testosterone on offer and rejection behaviour may be due to several other factors, including sex (i.e., male sample 11, 15, 16, 18 vs. female sample 15, 17, 19 ), and whether testosterone is endogenous or exogenous (i.e., measured salivary testosterone 11, 15 vs. administered testosterone 16–19 ). Another possibility is that subtle cues of interdependency influence the responder’s rejection behaviour.…”

Testosterone and human behavior: the role of individual and contextual variables

“…Two correlational studies have reported that men and women with relatively high baseline concentrations of testosterone are more likely to reject unfair offers [38,39]. In contrast, pharmacological challenge research in both men and women have not found these effects of testosterone on rejection behavior in the ultimatum game [40,41,42,22]. In a recent study [43], researchers investigated the effect of exogenous testosterone on men's punishment and reward behavior following unfair and fair offers in the ultimatum game.…”