Biological market theory has in recent years become an important part of the social evolutionist’s toolkit. This article discusses the explanatory potential and pitfalls of biological market theory in the context of big picture accounts of the evolution of human cooperation and morality. I begin by assessing an influential account that presents biological market dynamics as a key driver of the evolution of fairness norms in humans. I argue that this account is problematic for theoretical, empirical, and conceptual reasons. After (...) mapping the evidential and explanatory limits of biological market theory, I suggest that it can nevertheless fill a lacuna in an alternative account of hominin evolution. Trade on a biological marketplace can help explain why norm-based cooperation did not break down when our late-Pleistocene ancestors entered new, challenging social and economic environments. (shrink)

Can human social cognitive processes and social motives be grasped by the methods of experimental economics? Experimental studies of strategic cognition and social preferences contribute to our understanding of the social aspects of economic decisions making. Yet, papers in this issue argue that the social aspects of decision-making introduce several difficulties for interpreting the results of economic experiments. In particular, the laboratory is itself a social context, and in many respects a rather distinctive one, which raises questions of external validity.

The standard theories of cooperation in humans, which depend on repeated interaction and reputation effects among self-regarding agents, are inadequate. Strong reciprocity, a predisposition to participate in costly cooperation and the punishment, fosters cooperation where self-regarding behaviors fail. The effectiveness of socially coordinated punishment depends on individual motivations to participate, which are based on strong reciprocity motives. The relative infrequency of high-cost punishment is a result of the ubiquity of strong reciprocity, not its absence.

The emotion of anger has a long love–hate relationship with morality. On the one hand, anger often motivates us to sanction wrongdoing and uphold demanding moral standards. On the other hand, it can prompt aggression behaviors that are at odds with morality and even lead to moral disasters. This article describes this complex relationship. I argue that the intensity of anger elicited by moral transgressions is highly sensitive to key variables, including the identity of the person wronged, the nature of (...) the wrongdoing, and expectations about what should and will be done. Depending on the context, we sometimes experience more anger than would be commendable and sometimes less. These characteristics of anger, in turn, explain the ubiquity of norms and discourses aimed at governing the expression of this emotion. (shrink)

Experimental studies on punishment have sometimes been over-interpreted not only for the reasons Guala lists, but also because of a frequent conflation of proximate and ultimate explanatory levels that Guala's review perpetuates. Moreover, for future analyses we may need a clearer classification of different kinds of punishment.

The belief in immanent justice is the expectation that the universe is designed to ensure that evil is punished and virtue rewarded. What makes this belief so ‘natural’? Here, we suggest that this intuition of immanent justice derives from our evolved sense of fairness. In cases where a misdeed is followed by a misfortune, our sense of fairness construes the misfortune as a way to compensate for the misdeed. To test this hypothesis, we designed a set of studies in which (...) we show that people who do not believe in immanent justice are nonetheless implicitly influenced by intuitions of immanent justice. Strikingly, this effect disappears when the misfortune is disproportionate compared to the misdeed: In this case, justice is not restored and participants lose the intuition of immanent justice. Following recent theories of religion, we suggest that this intuition contributes to the cultural success of beliefs in immanent justice. (shrink)

Strong reciprocity theorists claim that punishment has evolved to promote the good of the group and to deter cheating. By contrast, weak reciprocity suggests that punishment aims to restore justice (i.e., reciprocity) between the criminal and his victim. Experimental evidences as well as field observations suggest that humans punish criminals to restore fairness rather than to support group cooperation.

Our discussion of the commentaries begins, at the evolutionary level, with issues raised by our account of the evolution of morality in terms of partner-choice mutualism. We then turn to the cognitive level and the characterization and workings of fairness. In a final section, we discuss the degree to which our fairness-based approach to morality extends to norms that are commonly considered moral even though they are distinct from fairness.

In the past decade, experiments on altruistic punishment have played a central role in the study of the evolution of cooperation. By showing that people are ready to incur a cost to punish cheaters and that punishment help to stabilise cooperation, these experiments have greatly contributed to the rise of group selection theory. However, despite its experimental robustness, it is not clear whether altruistic punishment really exists. Here, I review the anthropological literature and show that hunter-gatherers rarely punish cheaters. Instead, (...) they avoid dealing with them and switch to other partners. I suggest that these data are better explained by individual selection, and in particular by partner choice models, in which individuals are in competition to be recruited by cooperative partners. I discuss two apparent problems for partner choice theories: large-scale cooperation and punishments in economic games. I suggest that rather than favouring group selection theory, these two phenomena provide evidence in favour of individual selection: (1) people produce large-scale cooperation through institutions in which punishment is not altruistic but rewarded on an individual basis; (2) punishment in experimental games can be explained without altruism and is indeed often better explained by individual interests. (shrink)

What makes humans moral beings? This question can be understood either as a proximate question or as an ultimate question. The question is about the mental and social mechanisms that produce moral judgments and interactions, and has been investigated by psychologists and social scientists. The question is about the fitness consequences that explain why humans have morality, and has been discussed by evolutionary biologists in the context of the evolution of cooperation. Our goal here is to contribute to a fruitful (...) articulation of such proximate and ultimate explanations of human morality. We develop an approach to morality as an adaptation to an environment in which individuals were in competition to be chosen and recruited in mutually advantageous cooperative interactions. In this environment, the best strategy is to treat others with impartiality and to share the costs and benefits of cooperation equally. Those who offer less than others will be left out of cooperation; conversely, those who offer more will be exploited by their partners. In line with this mutualistic approach, the study of a range of economic games involving property rights, collective actions, mutual help and punishment shows that participants' distributions aim at sharing the costs and benefits of interactions in an impartial way. In particular, the distribution of resources is influenced by effort and talent, and the perception of each participant's rights on the resources to be distributed. (shrink)