Men have deep voices, women less so. This is a pretty basic fact that most small children will be able to tell you, but what we don’t often think about is that this is a very clear sexual dimorphism (and therefore likely evidence for sexual selection)! This vocal dimorphism is not just further evidence for size dimorphism, though it is true that in general larger vocal cords produce deeper sound: analysis has been done, and men’s voices are, pound for pound, deeper than womens’.
The study we read was about research done by David Andrew Puts, Steven J.C. Gaulin, and Katherine Verdolini (“Dominance and the evolution of sexual dimorphism in human voice pitch,” Evolution and Human Behavior 27 (2006) 283-296) to assess whether intrasexual selection may have affected the evolution of males’ deep voices. [Intrasexual selection is that between males, specifically in competition with each other for mates.] They found that men judged others as more dominant if the other had a deeper voice and that men modulated their vocal pitch between interactions with other men depending on whether they identified the other man as more or less dominant than themselves.
The researchers had men “compete” with a computer for a date and compared their pitches in this interaction to a pre-recorded baseline; the competitive recording was compared with the baseline and what the men felt about the dominance of their opponent; this gave the between-interaction results. A second group of men listened to a mix of the original competitive recordings and competitive recordings with the pitch raised or lowered and then rated the men who owned the voices on physical and social dominance scales–from strongly disagree to strongly agree with the statement “If this man got in a fistfight with an average male undergraduate student, this man would probably win” and a more complicated rating process for social dominance.
Our discussion centered in on a couple of problems we have with this study or the concept in general. Firstly, we became nervous that this trend for men to think deep voices were dominant could be–or at least could be suggested to be–cultural. We agreed with the authors that cross cultural studies as cultural controls would be helpful, and would likely assuage this fear, which is only slight as “the widespread association between dominance and pitch across animal species, including nonhuman primates (Morton, 1977; Morton & Page, 1992), and the cross-cultural universality of voice pitch sexual dimorphism, masculine vocal traits such as low pitch are expected to increase perceived physical dominance among men generally, with cultural variables influencing the degree, but not the direction, of this effect.”
Want more details? Read the study:
Puts, David Andrew, Steven J.C. Gaulin, and Katherine Verdolini. “Dominance and the evolution of sexual dimorphism in human voice pitch.” Evolution and Human Behavior. Vol. 27 (2006), pp 283-296.
