Testosterone rapidly increases men's emotion-based dehumanization of a conservatively dressed woman.

Past research has found that sexualized women are often dehumanized (i.e., attributed reduced human qualities). However, the mechanisms contributing to such dehumanization remain poorly understood. In this pre-registered experiment involving a within-subject, placebo-controlled, cross-over design, we tested whether testosterone contributes to men's (N = 120, age range: 18-38 years) dehumanization of women. After administration of intranasal testosterone or placebo gel, men watched a video of a woman wearing either modest (i.e., conservative) or revealing (i.e., sexualized) clothing (between-subjects factor) and then completed three subtle dehumanization tasks, measuring emotion-based, personality-based, and perceptual dehumanization. We hypothesized that testosterone would increase dehumanization, especially for men who watched the "sexualized-clothing" video. Instead, we found that, while men engaged in emotion-based dehumanization toward the sexualized woman both when they had testosterone and placebo, testosterone increased emotion-based dehumanization toward the conservatively dressed woman. Other forms of dehumanization were not affected by testosterone. We also explored whether personality (e.g., dominance) and biological (e.g., CAG repeat polymorphism) traits that have been found to moderate the effects of testosterone on some social behaviors also moderated the effects examined here, but we did not find any significant moderations. Overall, this experiment revealed a novel physiological mechanism affecting emotion-based dehumanization.