Testosterone Administration Moderates Effect of Social Environment on Trust in Women Depending on Second-to-Fourth Digit Ratio

Abstract

Animal research has established that effects of hormones on social behaviour depend on characteristics of both individual and environment. Insight from research on humans into this interdependence is limited, though. Specifically, hardly any prior testosterone experiments in humans scrutinized the interdependency of testosterone with the social environment. Nonetheless, recent testosterone administration studies in humans repeatedly show that a proxy for individuals’ prenatal testosterone-to-estradiol ratio, second-to-fourth digit-ratio (2D:4D ratio), influences effects of testosterone administration on human social behaviour. Here, we systematically vary the characteristics of the social environment and show that, depending on prenatal sex hormone priming, testosterone administration in women moderates the effect of the social environment on trust. We use the economic trust game and compare one-shot games modelling trust problems in relations between strangers with repeated games modelling trust problems in ongoing relations between partners. As expected, subjects are more trustful in repeated than in one-shot games. In subjects prenatally relatively highly primed by testosterone, however, this effect disappears after testosterone administration. We argue that impairments in cognitive empathy may reduce the repeated game effect on trust after testosterone administration in subjects with relatively high prenatal testosterone exposure and propose a neurobiological explanation for this effect.

Digit ratio (2D : 4D) and prosocial behaviour in economic games: no direct correlation with generosity, bargaining or trust-related behaviours

“…These examples are in line with the status-or dominance-related interpretation of the 2D : 4D-behaviour linkage [74]. According to this interpretation, fetal testosterone mainly manifests itself through enhancing the sensitivity to its circulating counterpart, supported by the observation that administered testosterone only affects low 2D : 4D individuals ( [77,78]; see also [76]). The role of circulating testosterone in status-related situations is widely documented [22,23,27].…”

Trust Game Database: Behavioral and EEG Data From Two Trust Games

“…In an OTG, the trustor's decisions are in response to a different trustee in each round, which simulated the trust behaviors among strangers. While in an ITG, each trustor plays with the same trustee over multiple rounds, and this simulated the trust behaviors among acquaintances (Rousseau et al, 1998;Buskens et al, 2016). Current Trust Game Databases provided the demographic data, behavioral data and raw EEG data (.cnt format; Neuroscan Inc.) of 40 healthy Chinese participants while they played the role of the trustor in OTG or ITG.…”

“…All these datasets can be freely downloaded from the open-access repository (Dryad Digital Repository, https://datadryad.org/stash/share/I4_ 9eQgXJL0sjukj8I9ruT2TToTZ90RuZvSmJO5LnyY). Previous studies have proposed that the one-shot trust and iterated trust simulated the generalized trust between strangers and specific trust between acquaintances, respectively (Rousseau et al, 1998;Buskens et al, 2016). In this sense, the current database may be used to examine the potential neural-dynamical differences between these two basic trust modes.…”

College-aged women in the United States that play overhand throwing sports have masculine digit ratios

“…(a) A variety of studies have demonstrated negative correlations between 2D:4D and athletic prowess and participation in competitive sports [ 36 , 45 , 45 ]. (b) 2D:4D may be negatively correlated with temporary increases in circulating testosterone in men during “challenge” situations similar to those experienced during athletic competition [ 62 ] and greater sensitivity to levels of circulating testosterone in both men and women [ 63 – 65 ]. (c) Competitive social interactions are positively correlated with testosterone exposure [ 66 , 66 – 68 ].…”