By Elizabeth Landau
CNN.com Health Writer/Producer
Some guys sound tough – and according to a new study, that may a good way of predicting whether they really are.
Results in the current Proceedings of the Royal Society B found that people can accurately evaluate the upper-body strength based on men’s voices from four different populations and language groups. The voice samples came from the Tsimane of Bolivia, Andean herder-horticulturalists from Argentina, and college students from the United States and Romania.
Researchers recorded body size and strength measurements from women and men in each of these groups. These participants also reported how many fights they had been involved in during the last four years.
Then, undergraduates from the University of California, Santa Barbara, rated the voices on physical strength, height and weight. For the sample of male voices from the United States, raters assessed “how tough he would be in a physical fight.”
The study found that, for the sample where data were available, the higher the perceived fighting ability, the more fights the man in the voice sample had reported being involved in during the last four years. It is not known how many fights these men won, but previous research suggests that “more formidable individuals are those more likely to engage in fights,” the authors wrote.]
For the rest of the samples, regardless of language spoken in the speech samples, participants rating the voices reported mostly accurate predictions for physical strength for men, but not for women. There was no significant difference between how good men and women were at evaluating the voices.
The results support the idea that the human voice, especially the male voice, has cues of physical strength, and that humans have evolved to be able to predict fighting ability based on those cues. This would have had great benefit to human ancestors, who may have used this information to their survival benefit – for instance, in choosing whom to fight with and whom not to confront.
Update: The study did not determine specifically what qualities in the voices were associated with greater strength. Researchers found, however, that pitch and timbre were not explanatory factors. In other words, contrary to what you might expect, lower pitch was not associated with greater perceived strength.