Abstract
The Cognitive Reflection Test (CRT) measures reliance on intuitive thinking versus deliberate reasoning and predicts important real-world outcomes. Prior research suggested that testosterone administration impaired CRT performance, but follow-up studies produced null results. To provide a rigorous test, we conducted an unprecedentedly large, preregistered, double-blind, placebo-controlled experiment with 1,000 men, as part of an adversarial collaboration. Participants received a single dose of intranasal testosterone or placebo, completed the CRT, and rated their confidence level. We find an insignificant treatment effect on the CRT, with the point estimate in the opposite direction of the original hypothesis (š¯›½LOGIT=0.118; 95%CI[-0.099, 0.335]). In a second primary test, we find a significant negative treatment effect on confidence (š¯›½LOGIT=-0.329; [-0.558, -0.100]), which is also opposite to our prediction. Our findings challenge earlier claims about testosteroneā€™s cognitive effects and highlight the importance of high-powered replications. Long-term or developmental testosterone effects remain potentially important but difficult to study.