Testosterone → Ultimatum rejection
Exogenous T changes bargaining — but not in the folk direction, and not in every lab.
Randomized trial · Contested · N=121
Supported by an experiment or a tightly identified design. Still read the caveats.
Mechanism
The brief's 'Camerer et al.' pointer is a misattribution. The Nature RCT is Eisenegger, Naef, Snozzi, Heinrichs, and Fehr (2010): T made women's proposals *fairer*. Belief that one got T made them *less* fair. Zak (2009) found less male generosity. Cueva et al. (2017) found no rejection-rate effect in men. The identified claim is 'T is not the aggression potion'; the signed effect on rejection is not settled.
Caveats
Different sexes, doses, timings, and roles (proposer vs responder). A 2020s reader should present the disagreement, not pick a camp. Camerer is a reproducibility author, not the T-ultimatum experimenter.
Effect
percent_change. Eisenegger: T increased fair offers in women. Zak: T decreased male generosity. Cueva: null on male rejections.
Nodes
Cite this page
What Causes What. “Testosterone → Ultimatum rejection.” https://whatcauseswhat.org/edges/e-t-ultimatum-rct (atlas updated 2026-08-31).
Papers
- Prejudice and truth about the effect of testosterone on human bargaining behaviour
C. Eisenegger, M. Naef, R. Snozzi, M. Heinrichs, E. Fehr · 2010 · Nature
- Testosterone administration decreases generosity in the ultimatum game
P. J. Zak, R. Kurzban, S. Ahmadi · 2009 · PLoS ONE
- Testosterone administration does not affect men's rejections of low ultimatum game offers or aggressive mood
C. Cueva, R. E. Roberts, T. J. Spencer, P. N. Tobler, A. Rustichini · 2017 · Hormones and Behavior