Sanfey, A. G. | Search bioRxiv

bioRxiv2026

Testosterone Administration Modulates Competitive Choice via Ventral Striatum and TPJ

How does testosterone influence decisions and choice-related neural computations in competitive environments? To address this question, we administered testosterone or placebo to female participants (n = 54) in a double-blind, randomized design. Following drug treatment, participants competed in a dot estimation task that manipulated opponent status (lower, equal, or higher) and outcome feedback (win or loss), after which they decided whether to compete against the same opponent again. All participants adjusted their behavior based on opponent status and outcome feedback. Participants who received testosterone, however, showed significantly greater sensitivity to outcome feedback: they were more willing to compete after winning and less willing after losing, and made those decisions faster - suggesting that testosterone increases the weighting of immediate, salient outcome information in competitive decision-making. At the neural level, a network comprising ventral striatum, vmPFC, bilateral TPJ and ACC processed outcome-related signals during the feedback period. Critically, neural prediction analyses at the trial-level revealed that activity in left ventral striatum and TPJ predicted subsequent decisions to compete, but only in participants who received testosterone. The direction of these effects mirrored the behavioral results: striatal activity amplified the tendency to re-compete after winning, whereas TPJ activity predicted renewed competition after losing. Together, these findings demonstrate that testosterone biases competitive decisions by amplifying the influence of outcome-related activity in reward and social cognition circuits.

neuroscience↗

bioRxiv2018

The Cost of Appearing Suspicious? Information Gathering Costs in Trust Decisions

Trust decisions are inherently uncertain, as people have incomplete information about the trustworthiness of the other prior to their decision. Therefore, it is beneficial to gather information about a trustees past behaviour before deciding whether or not to trust them. However, elaborate inquiries about a trustees behavior may change the trustees willingness to reciprocate, causing either a decrease due to the investor appearing suspicious, or an increase because the investor appears to be highly betrayal-averse. Such a change could cause the investor to gather less or more information, respectively. We examine how information acquisition is modulated by social context, monetary cost, and the trustees trustworthiness. Participants had the opportunity to sequentially sample information about a trustees reciprocation history before they decided whether or not to invest. On some trials, we induced a social context by telling the participant that the trustee would later learn how much the participant sampled (\"overt sampling\"). Participants sampled less when there was a monetary cost and when the reciprocation history was more conclusive. Crucially, when sampling was free and overt, participants sampled less, suggesting negative consequences of appearing suspicious. In post-experiment questionnaires, participants indeed reported a belief that the reciprocation probability would decrease when information was overtly sampled. The findings replicated in a second experiment and were well accounted for by a utility-maximizing model in which overt sampling induces a decrease in reciprocation probability. This study opens the door to broader applications of the tools and models of information sampling to social decision-making.\n\nSignificance StatementTrust and reciprocity are essential for establishing and maintaining beneficial cooperative interactions. However, not everyone can be trusted. Here, we focus on a fundamental question in the study of social interaction: how people gather and use information to make a decision to trust or not trust. While more information seems better, participants gathered less information about trustworthiness when the trustee would learn about the inquiries, as if they avoided appearing suspicious. Indeed, participants reported that they believed that sampling elaborately would make the trustee less willing to reciprocate trust. Using a mathematical model of information gathering, we show that this belief indeed reduces the value of information. Our findings contribute to a deeper understanding of information gathering in social contexts.

neuroscience↗