Selection in species with aggressive social interactions favours the evolution of cognitive mechanisms for assessing physical formidability (fighting ability or resource-holding potential). The ability to accurately assess formidability in conspecifics has been documented in a number of non-human species, but has not been demonstrated in humans. Here, we report tests supporting the hypothesis that the human cognitive architecture includes mechanisms that assess fighting ability-mechanisms that focus on correlates of upper-body strength. Across diverse samples of targets that included US college students, Bolivian horticulturalists and Andean pastoralists, subjects in the US were able to accurately estimate the physical strength of male targets from photos of their bodies and faces. Hierarchical linear modelling shows that subjects were extracting cues of strength that were largely independent of height, weight and age, and that corresponded most strongly to objective measures of upper-body strength-even when the face was all that was available for inspection. Estimates of women's strength were less accurate, but still significant. These studies are the first empirical demonstration that, for humans, judgements of strength and judgements of fighting ability not only track each other, but accurately track actual upper-body strength.

Recent research has shown that humans, like many other animals, have a specialization for assessing fighting ability from visual cues. Because it is probable that the voice contains cues of strength and formidability that are not available visually, we predicted that selection has also equipped humans with the ability to estimate physical strength from the voice. We found that subjects accurately assessed upper-body strength in voices taken from eight samples across four distinct populations and language groups: the Tsimane of Bolivia, Andean herder-horticulturalists and United States and Romanian college students. Regardless of whether raters were told to assess height, weight, strength or fighting ability, they produced similar ratings that tracked upper-body strength independent of height and weight. Male voices were more accurately assessed than female voices, which is consistent with ethnographic data showing a greater tendency among males to engage in violent aggression. Raters extracted information about strength from the voice that was not supplied from visual cues, and were accurate with both familiar and unfamiliar languages. These results provide, to our knowledge, the first direct evidence that both men and women can accurately assess men's physical strength from the voice, and suggest that estimates of strength are used to assess fighting ability.

We test the theory that shame evolved as a defense against being devalued by others. By hypothesis, shame is a neurocomputational program tailored by selection to orchestrate cognition, motivation, physiology, and behavior in the service of: (i) deterring the individual from making choices where the prospective costs of devaluation exceed the benefits, (ii) preventing negative information about the self from reaching others, and (iii) minimizing the adverse effects of devaluation when it occurs. Because the unnecessary activation of a defense is costly, the shame system should estimate the magnitude of the devaluative threat and use those estimates to cost-effectively calibrate its activation: Traits or actions that elicit more negative evaluations from others should elicit more shame. As predicted, shame closely tracks the threat of devaluation in the United States (r = .69), India (r = .79), and Israel (r = .67). Moreover, shame in each country strongly tracks devaluation in the others, suggesting that shame and devaluation are informed by a common species-wide logic of social valuation. The shame-devaluation link is also specific: Sadness and anxietyemotions that coactivate with shame-fail to track devaluation. To our knowledge, this constitutes the first empirical demonstration of a close, specific match between shame and devaluation within and across cultures.shame | emotion | valuation | culture | evolutionary psychology I n all known foraging societies past and present, humans have lived embedded in dense networks of cooperative and competitive interactions, a condition that is believed to have prevailed during the evolution of our species (1-3). Individuals in such social ecologies suffered or prospered depending on the summed effects of the choices of others-such as when and how often to share food, to provide care for another's child, to defer in conflicts, and so on. Ancestrally, the difference between an individual reproducing successfully, struggling, or dying early would have depended (in part) on the degree to which others traded off their own welfare for the welfare of that individual.Over the last fifty years, evolutionary researchers have identified a number of selection pressures that favored the evolution of decision systems that regulate welfare trade-offs between individuals, including kin selection (4), reciprocity/exchange (5, 6), risk-pooling (2), parenting (7), mating (8), externality management (9), and the asymmetric war of attrition (10). These theories, in turn, led to the empirical discovery of various choice architectures that evolved to produce best-bet welfare trade-off decisions given the information available to the actor about a potential recipient [e.g., how to respond to cues of genetic relatedness; how to respond to cues predicting the recipient's ability to effectively assert and defend her or his interests; how to respond to cues indicating a potential partner tends to cheat or free-ride (11-16)].In short, favorable valuation by others was a critical resource for our anc...

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Evidence suggests that our foraging ancestors engaged in the small-scale equivalent of social insurance as an essential tool of survival and evolved a sophisticated psychology of social exchange (involving the social emotions of compassion and anger) to regulate mutual assistance. Here, we hypothesize that political support for modern welfare policies are shaped by these evolved mental programs. In particular, the compassionate motivation to share with needy nonfamily could not have evolved without defenses against opportunists inclined to take without contributing. Cognitively, such parasitic strategies can be identified by the intentional avoidance of productive effort. When detected, this pattern should trigger anger and down-regulate support for assistance. We tested predictions derived from these hypotheses in four studies in two cultures, showing that subjects’ perceptions of recipients’ effort to find work drive welfare opinions; that such perceptions (and not related perceptions) regulate compassion and anger (and not related emotions); that the effects of perceptions of recipients’ effort on opinions about welfare are mediated by anger and compassion, independently of political ideology; and that these emotions not only influence the content of welfare opinions but also how easily they are formed.