Male facial width is associated with death by contact violence: narrow-faced males are more likely to die from contact violence

Abstract

Male facial width-to-height ratio (bizygomatic width scaled for face height) is a testosterone-linked trait predictive of reactive aggression, exploitative behavior, cheating, deception, and dominance. We tested whether facial width was systematically related to cause of death in a forensic sample. We hypothesized that wider-faced males, being more aggressive and robust, would be less likely than narrower-faced males to die from contact violence (stabbed, strangled, or bludgeoned to death) compared with other forms of homicide. We tested this hypothesis in a forensic data sample covering 523 male and 339 female skeletons. In these data, men with narrower faces were more likely to have died as a consequence of homicides involving direct physical contact than men with wider faces. No such effect was found for women. This effect was found when considering all causes of mortality and when limiting the sample to homicides. This finding suggests that wider-faced males are less likely to die from male–male physical violence, perhaps because of their formidability. Our findings are discussed with reference to the previous literature indicating that facial width-to-height ratio is a marker for male dominance.

Introduction

Ratings of male facial dominance from photographs accurately predict fighting ability (Sell et al., 2009). Facial dominance can also be predictive of life history. For example, the facial dominance of West Point US Military cadets in the 1950s predicted their final military rank as well as the number of children that they would sire (Mueller & Mazur, 1996). Typical features of facial dominance, associated with perceived lack of warmth, lack of honesty, and lack of cooperation, have been masculinity (Perrett et al., 1998) and prominent cheekbones (Cunningham, Barbee, & Pike, 1990).

Recently, relationships have been found between male dominance, reactive aggression, and variation in cheekbone measurements. Variation in human male bone growth, specifically cranial growth, is related to testosterone effects in adolescence (Verdonck, Gaethofs, Carels, & de Zegher, 1999), and studies have shown that male bone growth across the zygomatic arches (bizygomatic width), measured as the ratio of facial width to height, is related to perceptions of aggression and exploitativeness (Carre et al., 2009, Carre et al., 2010, Stirrat and Perrett, 2010). This measure also predicts actual aggression (Carre & McCormick, 2008, but see Özener, in press), cheating and deception (Haselhuhn & Wong, 2011), and exploitation of others (Stirrat & Perrett, 2010) in competitive and economic contexts, as well as increased self-reported ability to win “a physical fight with a same sex peer”.

Fighting ability, or strength, also predicts a man's willingness to express anger towards others (Sell, Tooby, & Cosmides, 2009) and is therefore also likely to predict violence. Indeed, male facial width has been positively associated with measures of actual physical violence: in one study, !Kung San Bushmen with broader bizygomatic measures had been more often involved in violent interactions resulting in head scars than those men with narrower bizygomatic width (Christiansen & Winkler, 1992). The authors interpreted the head scars as a measure of willingness to engage in violent fights because, amongst other measures, testosterone measures were positively associated with the number of scars in these violent men.

Signaling dominance and deciphering signals of dominance appear to have evolved in several nonhuman species [e.g., Harris sparrows (Rohwer, 1975)] to reduce the costs of competing over dominance. Accurately assessing a rival and avoiding a fight are likely to be less costly than losing a fight with a severe injury (Dawkins & Krebs, 1978). Signals of dominance may evolve in conditions where the cost of fighting (e.g., death) is greater than the benefit of the resource that is fought over (Maynard Smith & Harper, 1988)—although recent models suggest that signaling may be stable even over very high value resources and low costs of conflict where there are also high levels of commitment to defending that resource (see Szamado, 2011). As it has been found in a number of small-scale human societies that up to a third of men die as a result of violent encounters (Keeley, 1996), we might therefore expect that a cue to physical dominance such as facial width-to-height ratio would be a relevant parameter in human evolution. Given the foregoing comments about associations between facial width and anger (Sell, Tooby et al., 2009), violence (Christiansen & Winkler, 1992), and dominance (Mueller & Mazur, 1996), it would seem likely that wider-faced men are more willing to enter aggressive encounters and that they will do so because they are more likely to survive such encounters.

We therefore set out to test whether wider-faced men are more likely to survive aggressive encounters. We predicted that men who die from physically violent encounters, such as beating, strangulation, blunt force trauma, or stabbing, are likely to have a narrower facial width-to-height ratio when compared with those who die from technological causes such as poisoning or gunshot wounds, which would not favor men with either wide or narrow faces. We tested this hypothesis in a forensic anthropology data set (Jantz & Moore-Jansen, 2006). This database has detailed measurements of skeletal remains associated with cause of and age at death. We predicted that the skeletal remains of male homicide victims, who died from contact violence, would have narrower facial width-to-height ratios than those who died from other causes. More importantly, within homicide victims, we predicted that those who died from contact violence would have a lower relative facial width-to-height ratio than those who died from other causes of homicide (such as gunshot wounds). Even if wider-faced males are more likely to engage in aggressive encounters, we predicted them to be better able to survive direct physical confrontations but not better able to survive more indirect forms of violence. We also predicted that there would be no such relationship between female facial width-to-height ratio and cause of death.