The Evolution of Norms

The mentalizing network orchestrates the impact of parochial altruism on social norm enforcement

“…For instance, humans are willing to punish violators of social norms even at substantial personal costs [Boyd et al, 2003;Fehr and Gächter, 2002;Henrich, 2006]. A key element of the enforcement of many social norms, such as food-sharing norms in hunter-gatherer societies [Hill, 2002;Kaplan et al, 2000], is that people punish norm violators not only for direct transgressions against the punisher himself (termed second-party punishment), but also for norm violations against others (termed third-party punishment) [Bendor and Swistak, 2001;Sober and Wilson, 1998]. Norm enforcement requires that even third parties-who are neither economically, physically, nor psychologically affected by the violations-be willing to punish [Fehr and Fischbacher, 2004b;Henrich et al, 2006].…”

“…Thus, third-party punishment greatly enhances the scope for norms that regulate human behavior. In fact, some researchers view the existence of third-party sanctions as the decisive factor for the enforcement of social norms in human society because second-party punishment strategies are not evolutionarily stable, while strategies involving third-party sanctions are stable [Bendor and Swistak, 2001].…”

“…In these studies there was thus no trade off between the individual punisher's self-interest, which suggests that he should not punish at all, and the punisher's altruistic concerns, which suggest that he should protect the victim of norm violations. It is exactly this willingness to incur the cost of altruistic norm enforcement which renders altruistic third-party punishment a powerful evolutionary force ( [Bendor and Swistak, 2001;Sober and Wilson, 1998]. …”

The Adaptive Rationality of Interpersonal Commitment

“…While dyadic strategies are not eternally stable, it has also been shown that reciprocal dyadic strategies (including commitment) can be relatively more stable (but not perfectly stable) compared to non-reciprocal strategies. At the same time, Bendor and Swistak (2001) do not deny that social strategies impose a higher burden of cognitive complexity and information gathering on agents than do dyadic strategies. To the extent that this creates fitness costs, the advantage of social strategies may turn into a disadvantage.…”

“…Previous theoretical work may suggest, in particular, that the viability of commitment is seriously hampered by the 'dyadic' nature of this strategy. Bendor and Swistak (2001) have shown that dyadic strategies (strategies that only sanction defections that cause harm to the sanctioner) can never be evolutionarily stable, while 'social strategies' that also sanction noncooperation between third parties are stable. In a nutshell, the reason is that social strategies leave no room for benefiting from second-order free riding because a second-order free-rider would be punished by every compliant group member.…”