Them’s Fighting Words

A UCSB-lead study, published in the current issue of the Proceedings of the Royal Society B, has concluded that men and women can determine the upper body strength and fighting ability of men just by hearing their voices.

Undergraduate students from UCSB listened to voice samples from Tsimane hunter-horticulturalists in Bolivia, Andean herder-horticulturalists in Argentina, and college students from the US and Romania, and rated physical strength, fighting ability, height, and weight on a seven-point scale based on the voice samples alone.

The study team then compared these ratings to the actual measurements of the voices’ subjects. The most similar and accurate estimated measurements among all the test-takers were the ones on upper-body strength, more so than with height and weight. The degree of accuracy was the same for all samples, despite differences in language and culture.

The study’s concept was not unfamiliar. Over a dozen studies in the last fifty years have tested the ability of people to estimate height and weight from the voice, but they produced inconsistent results. Aaron Sell, a postdoctoral fellow at UCSB’s Center of Evolutionary Psychology and part of the study team, says in a press release the team’s findings indicate that these past studies “were looking at wrong variables” since they focused on size instead of fighting ability.

Sell claims that the ability to assess strength through hearing arose from natural selection since at times in human history, the ability to assess strength through visual cues would have been hampered. Even with a visual, the team found that it was easier to assess men’s strength with auditory clues as well. Sell stated in a press release that indicates “the voice contains some cues of strength that are invisible to the eye.”

The study found it was harder for women’s fighting levels to be correctly identified. The team claims this is because it has not been as important to assess women’s strength since men have been more involved in violence throughout human history.

The study contributed to a larger effort that examines the parts of the brain that assess fighting ability. Sell conducted the study with Greg Bryant, Leda Cosmides, John Tooby, Michael Gurven, graduate students Daniel Sznycer, Christopher von Rueden, and professor at the University of Timisoara in Romania Andre Krauss.