Data from: Testosterone eliminates strategic prosocial behavior in healthy males

Humans are strategically more prosocial when their actions are being
watched by others than when they act alone. Using a psychopharmacogenetic
approach, we investigated the computational and endocrinological
mechanisms of such audience-driven prosociality. 187 male participants
received either a single dose of testosterone or a placebo and performed a
prosocial and self-benefitting reinforcement learning task. Crucially, the
task was performed either in private or when being watched. Rival
theories suggest that the hormone might either diminish or strengthen
audience-depended generosity. We show that exogenous testosterone fully
eliminated strategic, i.e., feigned, generosity and thus decreased
submission to audience expectations. We performed reinforcement-learning
drift-diffusion computational modeling to elucidate which latent aspects
of decision-making testosterone acted on. The modeling revealed that
testosterone compared to placebo did not deteriorate reinforcement
learning per se, rather, when being watched, the hormone altered
the degree to which the learned information on choice value translated to
action selection. This indicates that when being watched, the hormone was
influencing participants towards choices that are less optimal for
prosociality, which resulted in nonconforming behavior. Indeed,
exploratory personal values analysis suggests that the effect of
testosterone in our reinforcement learning task is underpinned by a shift
from socially conforming to nonconforming decisions. Together, these
results indicate that instead of deceptively increasing socially desirable
behavior, testosterone - by acting on situational personal values -
counteracts submission to audience expectations, despite plausible
reputational costs.