The evolution of shame and guilt

Libing Shen,Chris T Bauch

doi:10.1371/journal.pone.0199448

Abstract

Shame and guilt seem to be two synonymous moral emotions but actually lead to contrasting human behaviors or behavioral tendencies. Shame drives people to hide or deny their wrongdoings while guilt drives people to amend their mistakes. How shame and guilt evolved in humans is still obscure. Here we present a computer model featured with reciprocal altruism and gregarious lifestyle for studying this question. We tested ten different strategies in our model and the pairwise contests show that shame-driven-hiding strategy can dominate the other strategies such as tit-for-tat and Pavlov in more than half of parameter combinations. The mathematical analysis of our model demonstrates that shame-driven-hiding strategy is an evolutionary stable strategy within a group as long as hiding can let an individual evade the retaliations to his wrongdoings. However, the problem of hiding is that it reduces an individual’s social circle, i.e. living in a smaller group. Our analysis also shows that guilt-driven-amending strategy can outperform shame-driven-denying strategy at both individual and group levels if the cooperative behavior is sustainable within a group (b/(b-c) < T/n). Thus, we propose that shame is more adaptive at the individual level while guilt is more advantageous in the context of intergroup competition.

Highlights

Moral emotions deeply influence our decision-making process and substantially regulate our social behaviors [1,2,3]
The mathematical analysis of our model demonstrates that shame-drivenhiding strategy is an evolutionary stable strategy within a group as long as hiding can let an individual evade the retaliations to his wrongdoings
Shame and guilt are two prominent moral emotions, because they serve as the conscience bases for different cultures [5]

Summary

Introduction

Moral emotions deeply influence our decision-making process and substantially regulate our social behaviors [1,2,3] They differ from basic emotions such as happiness and sadness in terms of requiring the understanding of other peoples’ mentalities [4]. Shame and guilt are two prominent moral emotions, because they serve as the conscience bases for different cultures [5]. Both shame and guilt are negative and painful emotions making them seem to be equivalents and their differences are constantly overlooked by many people [1, 2]. Shame and guilt do overlap in some psychological symptoms such as depression and selfderogation while they show different psychological trends, e.g. psychoticism vs. anxiety, and are accompanied by different physiological correlates, e.g. distinct immunological effects

Methods

Results

Conclusion