Does testosterone impair men's cognitive empathy? Evidence from two large-scale randomized controlled trials

The capacity to infer the mental states of others (known as cognitive empathy) is essential for social interactions, and a well-known theory proposes that it is negatively affected by intrauterine testosterone exposure. Furthermore, previous studies reported that testosterone administration impaired cognitive empathy in healthy adults, and that a biomarker of prenatal testosterone exposure (finger digit ratios) moderated the effect. However, empirical support for the relationship has relied on small-sample studies with mixed evidence. We investigate the reliability and generalizability of the relationship in two large-scale double-blind placebo-controlled experiments in young men (N=243 and N=400), using two different testosterone administration protocols. We find no evidence that cognitive empathy is impaired by testosterone administration or associated with digit ratios. With an unprecedented combined sample size, these results counter current theories and previous high-profile reports, and demonstrate that previous investigations of this topic have been statistically underpowered. ; © 2019 The Authors. Published by the Royal Society. Manuscript received 08/05/2019; Manuscript accepted 12/08/2019; Published online 04/09/2019; Published in print 09/2019. Ethics: The institutional review boards of Caltech and Claremont Graduate University approved the study, all participants gave informed consent, no adverse events occurred during any experimental session and no participant or researcher was harmed. For experiment 2, the study was approved by the Nipissing University Research Ethics Board. Data accessibility: Data are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.jm6qd39 [57] and the Open Science Framework (https://osf.io/hztfe). Authors' contributions: A.N. and G.N.: experimental design, manuscript and data analysis; C.F.C.: manuscript; D.T.Z.: manuscript and hormonal assay; T.L.O.: experimental design, data collection and hormonal assay; N.V.W.: manuscript; J.M.C.: experimental ...