How people judge attraction and threat often happens in seconds, long before a word is spoken. New research suggests that for men, physical cues such as height, body shape and even penis size quietly shape how they are perceived by both potential partners and rivals.
The study, published in PLOS Biology, explored how these traits influence perceptions of male attractiveness and fighting ability. Rather than relying on photographs or self reports, researchers used hundreds of computer generated male figures that varied systematically in height, body shape and penis size. Participants then rated what they saw, offering a rare experimental test of long debated ideas about sexual selection in humans.
More than 800 people took part, including men and women. Some viewed life sized projections in person, while others completed the task online. Women rated how attractive they found each figure. Men rated how threatened they would feel by the figure or how jealous they would be if he interacted with a partner.
Across all settings, a clear pattern emerged. Taller men with broader shoulders relative to their hips were consistently judged as more attractive and more physically formidable. Penis size also mattered. Figures with a larger penis were rated as more attractive by women and more threatening by men, even when height and body shape were taken into account.
The effect was strongest for body shape, followed by height, with penis size playing a smaller but still measurable role. Importantly, the influence of penis size did not operate in isolation. It amplified perceptions when combined with height and a V shaped torso, suggesting that people read these traits together rather than separately.
One striking finding was that men appeared to factor penis size into assessments of fighting ability. Men reported feeling more threatened by rivals with a larger penis, indicating that genital size may act as a subtle signal of dominance or confidence. This challenges the assumption that penis size is only relevant to sexual attraction and not to social competition.
Women’s judgements showed a slightly different pattern. While larger traits were preferred, the benefits levelled off at the upper end. In other words, bigger was better up to a point, after which attractiveness gains slowed. Men, by contrast, tended to assume that attractiveness and threat kept increasing steadily with size, suggesting that men may overestimate how much women value extreme traits.
The study also found that life sized figures produced stronger effects than small images viewed online. Seeing a body at realistic scale appeared to sharpen judgements, especially for height. This has implications for how researchers study attraction and dominance in a digital age where screens often replace real world encounters.
The findings help explain why certain male traits are so culturally charged. They also suggest that human sexual selection may have been shaped not only by mate choice but by competition between men. While culture, personality and social status clearly matter, the study shows that basic physical cues still play a role in how men are assessed at first glance.