Penis size interacts with body shape and height to influence male attractiveness - PMC
Compelling evidence from many animal taxa indicates that male genitalia are often under postcopulatory sexual selection for characteristics that increase a male’s relative fertilization success. There could, however, also be direct precopulatory ...
pmc.ncbi.nlm.nih.gov
Core Finding: This study found that penis size, height, and body shape (shoulder-to-hip ratio) all significantly influence male sexual attractiveness, and these traits interact with each other in complex ways. It suggests that female mate choice could have played a role in the evolution of larger penis size in humans.
Key Aspects of the Study
- Premise: The study addresses the question of whether female mate choice influences the evolution of male genital traits, specifically penis size in humans. The visibility of the human penis makes it a potential target for sexual selection.
- Methodology:
- Researchers presented heterosexual Australian women with life-size, computer-generated, animated male figures.
- The figures varied in flaccid penis size, shoulder-to-hip ratio, and height. Each trait had seven possible values within a natural range. A total of 343 figure combinations were created.
- Women viewed a random subset of 53 figures and rated their attractiveness as sexual partners on a Likert scale.
- The study used evolutionary selection analyses to estimate linear, nonlinear, and correlational selection based on attractiveness scores.
- Results:
- Linear Effects: Height, penis size, and shoulder-to-hip ratio all had significant positive linear effects on male attractiveness. A larger shoulder-to-hip ratio had the strongest effect.
- Nonlinear Effects: There were diminishing returns to increases in height, penis size, and shoulder-to-hip ratio, suggesting that attractiveness doesn't increase indefinitely with larger sizes.
- Correlational Selection: The effects of the three traits were not independent.
- The effect of penis size on attractiveness was greater for taller men.
- A similar relationship was found between penis size and shoulder-to-hip ratio.
- Participant Analysis:
- Women with higher relative weight (BMI) showed a stronger linear effect of penis size on male attractiveness.
- Response Time: Women took longer to rate figures with larger penis size, greater height, and greater shoulder-to-hip ratio.
- Discussion Highlights:
- Penis Size Matters: Flaccid penis size significantly influences male attractiveness, although the proportional increase in attractiveness decreases after a certain size.
- Height and Body Shape: The study confirmed previous findings that taller men and those with a greater shoulder-to-hip ratio are generally rated as more attractive.
- Relative Importance: Penis size and height had roughly equivalent effects on attractiveness, suggesting selection on penis size is potentially as strong as selection on stature. The shoulder-to-hip ratio had a larger effect, possibly due to the range of body shapes used.
- Trait Interactions: The effect of penis size on attractiveness is influenced by both height and body shape.
- Conclusion: The study provides evidence that penis size, in conjunction with height and body shape, plays a significant role in male sexual attractiveness, supporting the hypothesis that female mate choice may have influenced the evolution of penis size in humans.
