Social image concerns promote cooperation more than altruistic punishment.

Gianluca Grimalda,Andreas Pondorfer,David P Tracer

doi:10.1038/ncomms12288

Abstract

Human cooperation is enigmatic, as organisms are expected, by evolutionary and economic theory, to act principally in their own interests. However, cooperation requires individuals to sacrifice resources for each other's benefit. We conducted a series of novel experiments in a foraging society where social institutions make the study of social image and punishment particularly salient. Participants played simple cooperation games where they could punish non-cooperators, promote a positive social image or do so in combination with one another. We show that although all these mechanisms raise cooperation above baseline levels, only when social image alone is at stake do average economic gains rise significantly above baseline. Punishment, either alone or combined with social image building, yields lower gains. Individuals' desire to establish a positive social image thus emerges as a more decisive factor than punishment in promoting human cooperation.

Highlights

Human cooperation is enigmatic, as organisms are expected, by evolutionary and economic theory, to act principally in their own interests
We conducted a series of anonymous, one-shot, prisoner’s dilemma (PD) games involving two participants
We find that concerns about social image, here manifested by the actions that one takes in a one-shot PD game in the presence of a local authority, the Big Man’ (BM), promote efficiency significantly more than altruistic punishment

Summary

Introduction

As organisms are expected, by evolutionary and economic theory, to act principally in their own interests. The main drawback of reputational mechanisms is that they are only effective in communities where there is high ‘broadcast efficiency’, that is, reliable information about individuals’ past behaviours can diffuse rapidly through the community[31] We expect this to be most common in small, tight-knit communities where gossip travels quickly or where there exists an authority or institution that occupies a central position amid its social networks and serves as a conduit for disseminating information about people’s social images. It is interesting to investigate their relative efficacy in promoting social welfare, to shed light on the respective role that they can play to sustain human cooperation The evidence on this topic is scant and limited to few experiments where one’s social image is artificially created and maintained in the laboratory[22,39,40,41]. A compelling argument has been made[42] that these conditions are relatively novel within evolutionary history, and that data from non-Western small-scale societies are essential for testing hypotheses about human psychology, especially in the domains of preferences and decision-making

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Results

Conclusion