Human third-party observers accurately track fighting skill and vigour along their unique paths to victory

Sexual selection via male-male contest competition has shaped the evolution of agonistic displays, weaponry, and fighting styles, and is further argued to have shaped human psychological mechanisms to detect, process, and respond appropriately to cues of fighting ability. Drawing on the largest fight-specific dataset to date across the sports and biological sciences (N = 2,765), we examined how different indicators of fighting ability in humans reflect unique paths to victory and indicate different forms of perceived and actual resource-holding power (RHP). Overall, we discovered that: (1) both striking skill and vigour, and grappling skill and vigour, individually and collectively predict RHP; (2) different RHP indicators are distinguished by a unique path to victory (e.g., striking skill is a knockout-typical strategy, whereas grappling vigour is a submission-typical strategy); and (3) third-party observers accurately track fighting skill and vigour along their unique paths to victory. Our argument that different measures of RHP are associated with unique paths to victory, and third-party observers accurately track fighting vigour and skill along their unique paths to victory, advance our understanding not only of human contest competition, but animal contest theory more broadly.

Female emancipation in a male dominant, sexually dimorphic primate under natural conditions

In most group-living animals, a dominance hierarchy reduces the costs of competition for limited resources. Dominance ranks may reflect prior attributes, such as body size, related to fighting ability or reflect the history of self-reinforcing effects of winning and losing a conflict (the winner-loser effect), or both. As to prior attributes, in sexually dimorphic species, where males are larger than females, males are assumed to be dominant over females. As to the winner-loser effect, the computational model DomWorld has shown that despite the female’s lower initial fighting ability, females achieve some degree of dominance of females over males. In the model, this degree of female dominance increases with the proportion of males in a group. This increase was supposed to emerge from the higher fraction of fights of males among themselves. These correlations were confirmed in despotic macaques, vervet monkeys, and in humans. Here, we first investigate this hypothesis in DomWorld and next in long-term data of 9,300 observation hours on six wild groups of robust capuchin monkeys (Sapajus libidinosus; S. nigritus, and S. xanthosternos) in three Brazilian sites. We test whether both the proportion of males and degree of female dominance over males are indeed associated with a higher relative frequency of aggression among males and a higher relative frequency of aggression of females to males. We confirm these correlations in DomWorld. Next, we confirm in empirical data of capuchin monkeys that with the proportion of males in the group there is indeed an increase in female dominance over males, and in the relative frequency of both male-male aggression and aggression of females to males and that the female dominance index is significantly positively associated with male male aggression. Our results reveal that adult sex ratio influences the power relation between the sexes beyond predictions from socioecological models.

The Compleat Victory:

In the late summer and fall of 1777, after two years of indecisive fighting on both sides, the outcome of the American War of Independence hung in the balance. Having successfully expelled the Americans from Canada in 1776, the British were determined to end the rebellion the following year and devised what they believed a war-winning strategy, sending General John Burgoyne south to rout the Americans and take Albany. When British forces captured Fort Ticonderoga with unexpected ease in July of 1777, it looked as if it were a matter of time before they would break the rebellion in the North. Less than three and a half months later, however, a combination of the Continental Army and militia forces, commanded by Major General Horatio Gates and inspired by the heroics of Benedict Arnold, forced Burgoyne to surrender his entire army. The American victory stunned the world and changed the course of the war. In the end, British plans were undone by a combination of faulty strategy, distance, geography, logistics, and an underestimation of American leadership and fighting ability. Taking Ticonderoga had misled Burgoyne and his army into thinking victory was assured. The campaign’s outcome forced the British to rethink their strategy, inflamed public opinion in England against the war, boosted Patriot morale, and, perhaps most critical of all, led directly to the Franco-American alliance. Weddle unravels the web of contingencies and the play of personalities that ultimately led to what one American general called “the Compleat Victory.”

Contextual Factors that Heighten Interest in Coalitional Alliances with Men Possessing Formidable Facial Structures

Individuals use facial width-to-height ratio (fWHR) to infer dominance and fighting ability of others. We hypothesized that broad assessments of target formidability from fWHR would form a basis for determining men’s coalitional value, with high-fWHR men being especially valuable in roles requiring physical strength. Across five studies (N=1,445), we identified the social affordance of male facial structures connoting formidability and how judgments influence coalitional decisions. In addition to replicating previous findings indicating high-fWHR men are more desirable for tasks requiring physical strength, we found that such men are aversive for tasks requiring creativity (Studies 1 and 2). High-fWHR men were additionally perceived as more effective in combat roles in the military (Study 3). Finally, in two pre-registered studies, we found that activation of competitive motivations heightens individuals’ interest in formidable allies during intergroup interactions (Study 4), but not interest in approaching them (Study 5). We interpret findings using evolutionary and social affordance theories and discuss hypothesized ancestral origins of selecting formidable allies.

Low fundamental and formant frequencies predict fighting ability among male mixed martial arts fighters

Human voice pitch is highly sexually dimorphic and eminently quantifiable, making it an ideal phenotype for studying the influence of sexual selection. In both traditional and industrial populations, lower pitch in men predicts mating success, reproductive success, and social status and shapes social perceptions, especially those related to physical formidability. Due to practical and ethical constraints however, scant evidence tests the central question of whether male voice pitch and other acoustic measures indicate actual fighting ability in humans. To address this, we examined pitch, pitch variability, and formant position of 475 mixed martial arts (MMA) fighters from an elite fighting league, with each fighter’s acoustic measures assessed from multiple voice recordings extracted from audio or video interviews available online (YouTube, Google Video, podcasts), totaling 1312 voice recording samples. In four regression models each predicting a separate measure of fighting ability (win percentages, number of fights, Elo ratings, and retirement status), no acoustic measure significantly predicted fighting ability above and beyond covariates. However, after fight statistics, fight history, height, weight, and age were used to extract underlying dimensions of fighting ability via factor analysis, pitch and formant position negatively predicted “Fighting Experience” and “Size” factor scores in a multivariate regression model, explaining 3–8% of the variance. Our findings suggest that lower male pitch and formants may be valid cues of some components of fighting ability in men.