Human Adaptations for the Visual Assessment of Strength and Fighting Ability from the Body and Face

Center for Evolutionary Psychology, University of California, Santa Barbara, CA 93106, USA.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.05). 11/2008; 276(1656):575-84. DOI: 10.1098/rspb.2008.1177
Source: PubMed

ABSTRACT 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.

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Available from: Michael Gurven, Sep 29, 2015
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    • "Using a different sample of women, Gallup and Wilson (2009) found that objective raters perceived the faces of adolescents with higher BMI to be more aggressive. Similarly, Sell et al. (2009) found that objective raters could accurately predict women's handgrip strength from photographs of their faces, and were even more accurate when making judgments from photographs of full bodies. In addition, Fessler et al. (2014) showed that when naïve participants were asked to choose which target body best depicted a described risk-prone woman, they were significantly more likely to choose a taller and larger target than when asked to choose which woman depicted a described risk-averse woman. "
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    ABSTRACT: Several lines of evidence suggest that facial-width-to-height ratio (fWHR) provides an accurate cue to men's formidability, thus providing observers with a reliable estimate of their potential success in an interpersonal physical conflict. The degree to which fWHR provides the same information in women's faces, however, remains unclear. In fact, morphological characteristics, such as body size, may be more effective indicators of formidability in women. In the present study, we analyzed the effects of both fWHR and body mass index (BMI) on total number of fights and total number of wins in female competitive Ultimate Fighting Challenge (UFC) fighters. After controlling for number of active years fighting, we found that BMI significantly predicted number of wins in female fighters. The effects of fWHR were not significant, but warrant replication with a larger sample. These results suggest that in women, body size, rather than fWHR, may be a more accurate indicator of success in aggressive interpersonal conflicts. Our findings contribute to a growing body of literature that shows distinct differences in men and women's interpersonal aggressive and dominance behavior, as well as their morphological indicators. Keywords Facial width to height ratio (fWHR). Formidability. Physical strength. Female faces. Body mass index (BMI) Adaptive Human Behavior and Physiology
    09/2015; DOI:10.1007/s40750-015-0035-3
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    • "Conceptualizing the danger posed by others in terms of their size and strength should be intuitive, as these physical traits have predicted the outcomes of violent conflict throughout both phylogenetic history and ontogenetic experience (Archer, 1988; Sell et al., 2009; Unnever & Cornell, 2003). Supporting the existence of a system that represents threat using envisioned physical formidability, estimated size and strength are influenced by the possession of weapons deployed in reasoning about relative status, in a status representation system that operates similarly to the formidability representation system. "
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    ABSTRACT: We hypothesize that, paralleling the evolution of human hierarchies from social structures based on dominance to those based on prestige, adaptations for representing status are derived from those for representing relative fighting capacity. Because both violence and status are important adaptive challenges, the mind contains the ancestral representational system as well as the derived system. When the two representational tasks conflict, owing to the exigent nature of potential violence, the former should take precedence over the latter. Indeed, separate literatures indicate that, despite the fact that threatening traits are generally deleterious to prestige, both threatening individuals and high-status individuals are conceptually represented as physically large. We investigated the interplay between size-based representations of threat versus prestige by examining racial danger stereotypes. In three studies, we demonstrate that (a) judgments of status only positively correlate with envisioned body size for members of groups stereotyped as safe, (b) group-based inferences of interpersonal threat are mediated by representations of physical size, (c) controlling for perceived threatening aggressiveness reduces or reverses non-positive correlations between status and size, and (d) individuating information about relative threat or status attenuates the influence of group danger stereotypes. These results support our proposal that ancestral threat-representation mechanisms and derived mechanisms for representing social rank coexist – and sometimes compete – in the mind.
    Evolution and Human Behavior 09/2015; DOI:10.1016/j.evolhumbehav.2015.08.004 · 3.13 Impact Factor
    • "We, therefore, investigated how altering perceived height, masculinity, and age each influence perceptions of dominance in male faces. We hypothesized that faces of men who appeared to be tall would be assigned higher dominance ratings because taller men are physically stronger (Sell et al., 2009), are perceived as more dominant (Melamed, 1992), and behave in a more domineering way (Melamed, 1992). Given that dominance scores of male faces decline later in life (Mueller & Mazur, 1996), we predicted that the relationship between men's ages and their dominance ratings would follow an inverted-U pattern, with the highest ratings around age 30. "
    Perception 08/2015; DOI:10.1177/0301006615596898 · 0.91 Impact Factor
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