The Effect of Neuropeptides on Human Trust and Altruism: A Neuroeconomic Perspective

Abstract

Neuroeconomics merges methods from neuroscience and economics to better understand how the human brain generates decisions in economic and social contexts. The emerging neuroeconomic approach (Camerer et al. 2005; Fehr et al. 2005; Glimcher and Rustichini 2004; Sanfey et al. 2006) seeks a microfoundation behind social and economic activity in neural circuitry, using functional magnetic resonance imaging (fMRI), transcranialmagnetic stimulation (TMS), pharmacological interventions, and other techniques. Byproducts of such an ambitious program might include better understanding of individual pathologies in social behaviors, such as antisocial personality disorder or social phobia, and, more generally, poor individual decision-making abilities, including lacking the capacity to inhibit prepotent impulses. The approach may also provide insights into the effects of individual and social learning, empirical discipline of evolutionary modeling, and advice for how economic rules and institutions can be designed so that people react to rules in a socially efficient way. Here we review the actual and predicted impact of neuropeptides such as oxytocin and vasopressin on human trust and altruism. Traditional economic analyses generally make the simplifying assumption that people are exclusively self-regarding; however, a large body of experimental evidence (Fehr and Fischbacher 2003) has been amassed indicating that many people exhibit social preferences, i.e., their preferred choices are based on a positive or negative concern for the welfare of others and on what other players believe about them. Social neuroeconomics (Fehr and Camerer 2007) tries to understand the brain processes that govern these regular deviations from purely self-interested behavior. Part of this endeavor concerns studying the impact of hormones on other-regarding behaviors and trust in other people’s other-regarding behavior. Social neuroeconomics combines the tools of social cognitive neuroscience (Adolphs 2003; Blakemore et al. 2004; Lieberman 2007) with well-structured tasks taken from economic theory. These tasks come equipped with benchmark theoretical predictions about rational play and the social efficiency of outcomes, which are useful for interpreting the results and cumulating regularity across studies.