Neural Mechanisms of the Testosterone–Aggression Relation: The Role of Orbitofrontal Cortex

Abstract

Testosterone plays a role in aggressive behavior, but the mechanisms remain unclear. The present study tested the hypothesis that testosterone influences aggression through the OFC, a region implicated in self-regulation and impulse control. In a decision-making paradigm in which people chose between aggression and monetary reward (the ultimatum game), testosterone was associated with increased aggression following social provocation (rejecting unfair offers). The effect of testosterone on aggression was explained by reduced activity in the medial OFC. The findings suggest that testosterone increases the propensity toward aggression because of reduced activation of the neural circuitry of impulse control and self-regulation.

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

“…In our data, beliefs had no significant effect on rejection rates Evidence of a positive correlation between baseline T levels and low offer rejections was found in two previous studies (Burnham, 2007;Mehta and Beer, 2010). We reproduced their analysis using responses in the placebo condition and found no significant difference in (log) baseline T levels between subjects who accepted 2GBP offers, and those who rejected them, although the difference was in the same direction as the previous reports (t(30) = 0.26, one-sided p = 0.4, d = 0.10, 95% C.I.…”

“…Alternatively, Bayes factors can be computed to estimate the odds that the null model is correct relative to alternative models that assume a positive treatment effect. Basing our prior on the positive correlations between basal T and rejection rates reported in earlier studies (Burnham, 2007;Mehta and Beer, 2010), our evidence yields Bayes factors ranging from 4.84 to 28.29, which, according to commonly used evidence categories, constitute substantial and strong evidence in favor of the null model, respectively (see supplementary information).…”

“…In the context of the ultimatum game, the rejection of an unequal offer favoring the proposer has been interpreted as a form of non-physical aggression in response to social provocation (Burnham, 2007;Mehta and Beer, 2010). Thus, it is natural to formulate the hypothesis that elevated T will increase the probability of rejecting such offers.…”

“…Economists have developed various models to accommodate these findings, for instance by incorporating inequality aversion or fairness considerations into decision-makers' preferences (Fair and Schmidt, 1999;Rabin, 1993). However, ultimatum rejections have also been interpreted as a way in which individuals express anger (Xiao and Houser, 2005) and as non-physical aggression in response to social challenge (Burnham, 2007;Mehta and Beer, 2010).…”

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].…”