Testosterone promotes either dominance or submissiveness in the Ultimatum Game depending on players’ social rank

Yukako Inoue,Taiki Takahashi,Robert P Burriss,Sakura Arai,Toshikazu Hasegawa,Toshio Yamagishi,Toko Kiyonari

doi:10.1038/s41598-017-05603-7

Abstract

Endogenous testosterone promotes behaviours intended to enhance social dominance. However, recent research suggests that testosterone enhances strategic social behaviour rather than dominance seeking behaviour. This possibility has not been tested in a population whose members are known to vary in social status. Here, we explored the relationship between pre-existing social status and salivary testosterone level among members of a rugby team at a Japanese university, where a strong seniority norm maintains hierarchical relationships. Participants played a series of one-shot Ultimatum Games (UG) both as proposer and responder. Opponents were anonymised but of known seniority. We analysed participants’ acquiescence (how much more they offered beyond the lowest offer they would accept). The results showed that, among the most senior participants, higher testosterone was associated with lower acquiescence. Conversely, higher testosterone among the lower-status participants was associated with higher acquiescence. Our results suggest that testosterone may enhance socially dominant behaviour among high-status persons, but strategic submission to seniority among lower-status persons.

Highlights

Testosterone is a steroid hormone associated with aggression and dominance both in animals and humans
We used the pre-game measure of testosterone to analyse the relationship between testosterone and game behaviour, because the post-game measure may be affected by performance during the Ultimatum Games (UG)
This study is the first to demonstrate that endogenous testosterone is related to strategic social decision making that differs according to the decision maker’s status, by utilising an appropriate dependent variable measured with an economic game (i.e., “acquiescence” in the UG) with participants who belong to a strong pre-established social hierarchy

Summary

Introduction

Testosterone is a steroid hormone associated with aggression and dominance both in animals and humans. The aim of the present study is to examine how the link between testosterone and status-seeking motives affects the economic decision making of the members of a pre-existing and hierarchically-organised group This question has implications for neuroendocrinology and social neuroeconomics, since recent studies suggest that testosterone is related to strategic social behaviour, and that the conception of androgens as drivers of socially dominant and aggressive behaviour is too simplistic[7, 8]. Burnham[11] showed that lower offers in the UG were more often rejected by men with high levels of salivary testosterone, and suggested that the effect could be mediated by testosterone’s impact on status-asserting behaviour: low offers are interpreted by responders as a challenge to their status, and this challenge is more salient to responders high in testosterone. Because a rejected offer may lower the proposer’s status, high levels of testosterone may motivate proposers to avoid circumstances likely to lead to rejection

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