Perceptions of moral character modulate the neural systems of reward during the trust game

Abstract

Studies of reward learning have implicated the striatum as part of a neural circuit that guides and adjusts future behavior on the basis of reward feedback. Here we investigate whether prior social and moral information about potential trading partners affects this neural circuitry. Participants made risky choices about whether to trust hypothetical trading partners after having read vivid descriptions of life events indicating praiseworthy, neutral or suspect moral character. Despite equivalent reinforcement rates for all partners, participants were persistently more likely to make risky choices with the 'good' partner. As expected from previous studies, activation of the caudate nucleus differentiated between positive and negative feedback, but only for the 'neutral' partner. Notably, it did not do so for the 'good' partner and did so only weakly for the 'bad' partner, suggesting that prior social and moral perceptions can diminish reliance on feedback mechanisms in the neural circuitry of trial-and-error reward learning.

Seeing is believing: Trustworthiness as a dynamic belief

“…It is unlikely that many participants approached this task believing the person they saw was an active participant due to the rather dated nature of the photographs. However, people do appear to easily anthropomorphize when stimuli behave like real people (Blakemore & Decety, 2001), and more pointedly, the pattern of behavior that we observed is similar to all other reported versions of the repeated Trust Game (Delgado et al, 2005;King-Casas et al, 2005;Krueger et al, 2007). We interpret this to mean that people approached the task at least ''as if" they were playing with a real life partner.…”

“…Previous research has reported that both initial impressions (Delgado et al, 2005;van 't Wout & Sanfey, 2008) and direct experience (King-Casas et al, 2005;Singer et al, 2004) play important roles in influencing judgments of trustworthiness. This experiment provides the first account of how these variables interact in a social interactive financial investment game that has been explicitly designed to study trust (Berg et al, 1995).…”

“…One question that currently remains unanswered is the interaction between this initial assessment and the subsequent updating, for example, the degree to which each signal may contribute to the final trust decision, and how concordant (a trustworthy face engaged in reciprocal behavior) and conflicting (e.g., a trustworthy face who does not reciprocate) information is handled. No study has directly investigated this question in the context of a Trust Game, though one experiment has provided preliminary evidence suggesting that initial judgments may influence the way information from repeated interactions is updated (Delgado et al, 2005). In this study, participants played a repeated Trust Game with three fictional characters.…”

“…The process of placing trust when it has previously been reciprocated, but stopping once trust is abused, is often referred to as a tit-for-tat strategy, and has been demonstrated to be the optimal strategy for repeated interactions (Axelrod & Hamilton, 1981). Repeated interactions have also been shown to influence subjective ratings of moral character in a Prisoner's Dilemma game (Singer, Kiebel, Winston, Dolan, & Frith, 2004) and in a Trust Game (Delgado et al, 2005). These findings suggest that in a repeated interaction, trustworthiness can be learned based on the history of a partner's behavior.…”

“…The Confirmation Bias model proposes that initial implicit trustworthiness judgments influence the way feedback (i.e. non-reciprocated trust) is updated throughout the interactions (Biele et al, 2009;Delgado et al, 2005;Doll et al, 2009). This model assumes that learning is biased in the direction of the initial impressions.…”