The evolution of reciprocal altruism probably involved the evolution of mechanisms to detect cheating and remember cheaters. In a well-known study, Mealey, Daood, and Krage (1996) observed that participants had enhanced memory for faces that had previously been associated with descriptions of acts of cheating. There were, however, problems with the descriptions that were used in that study. We sought to replicate and extend the findings of Mealey and colleagues by using more controlled descriptions and by examining the possibility of (...) enhanced altruist recognition. We also examined whether individual differences in cheating tendencies were related to cheater and altruist recognition. In the first experiment, 164 undergraduates saw 40 faces that were paired with character descriptions representing the categories of cheater, trustworthy, altruist, or neutral, for individuals who had either low or high social status. One week later participants reported which faces they recognized from the previous week (among 80 faces). Overall, the results failed to replicate the findings of Mealey and her colleagues, as there was no enhanced memory for cheaters. In addition, there was no enhanced memory for altruists, and no effect of participants’ cheating tendencies. A second experiment using a slightly different methodology produced similar results, with some evidence for enhanced memory for altruists. (shrink)

While admirable, Guala's discussion of reciprocity suffers from a confusion between proximate causes (psychological mechanisms triggering behaviour) and ultimate causes (evolved function of those psychological mechanisms). Because much work on commits this error, I clarify the difference between proximate and ultimate causes of cooperation and punishment. I also caution against hasty rejections of of experimental evidence.

Physical attractiveness affects how one gets treated, but it is just a single component of one's overall “market value.” One's treatment depends on other markers of market value, including social status, competence, warmth, and any other cues of one's ability or willingness to confer benefits on partners. To completely understand biased treatment, we must also incorporate these other factors.

The “fearful ape hypothesis” is interesting but is currently underspecified. We need more research on whether it is specific to fear, specific to humans (or even cooperative breeders in general), what is included in “fear,” and whether these patterns would indeed evolve despite arms races to extract help from audiences. Specifying these will result in a more testable hypothesis.

One reason why humans don't behave according to standard game theoretical rationality is because it's not realistic to assume that everyone else is behaving rationally. An individual is expected to have psychological mechanisms that function to maximize his/her long-term payoffs in a world of potentially “irrational” individuals. Psychological decision theory has to be individualistic because individuals make decisions, not groups.

The target article's important point is easily misunderstood to claim that all revenge is adaptive. Revenge and forgiveness can overstretch the bounds of utility due to misperceptions, minimization of costly errors, a breakdown within our evolved revenge systems, or natural genetic and developmental variation. Together, these factors can compound to produce highly abnormal instances of revenge and forgiveness.

Henrich et al.'s nice cross-cultural experiments would benefit from models that specify the decision rules that humans use and the specific developmental pathways that allow cooperative norms to be internalized. Such models could help researchers to design further experiments to examine human social adaptations. We must also test whether the “same” experiments measure similar constructs in each culture, using additional methods and measures.

We extend Tomasello's framework by addressing the functional challenge of obligation. If the long-run social consequences of a decision are sufficiently costly, obligation motivates the actor to forgo potential immediate benefits in favor of long-term social interests. Thus, obligation psychology balances the downstream socially-mediated payoffs from a decision. This perspective can predict when and why obligation will be experienced.

Van de Vliert's findings may be explained by the psychology of threat and bargaining. Poor people facing extreme threats must cope by surrendering individual freedom in service of shared group needs. Wealthier people are more able to flee from threats and/or resist authoritarianism, so their leaders must concede greater freedom. Incorporating these factors (plus inequality) can sharpen researchers' predictions.