American scientists have found that the timbre of a man’s voice can accurately determine his physical strength, endurance and even aggressiveness. According to the paper, published in the journal Proceedings of the Royal Society B, the sound of the voice may have helped assess rivals in the early stages of human evolution. Although the specialists who conducted the research could not accurately determine which of all the parameters of the voice is indicative of the physical strength of the owner of one or another voice. The American experts found that both women and men belonging to different social groups coped equally well with the task of evaluating men’s physical data. The leader of the study Aaron Sell and his colleagues from the University of California conducted an experiment with men of different age and social groups, who had to say in their native language the phrase “This is an experiment, end of the relationship” without adding any emotion. Volunteers from the USA, Romanian students, hunting groups and collectors from Bolivia, Argentine farmers, etc. took part in the study. The second part of the experiment was conducted among women and men from the same cultural and ethnic groups. The participants had to rate on a scale of one to seven the physical strength and degree of aggression of the men in the first group, based solely on the sound of their voices. The data collected were compared with those from an independent assessment of the men’s physical strength and aggressiveness, based on strength exercises and psychological tests. The scientists were surprised to find that in more than 50% of the cases, the volunteers from the second group accurately determined the physical strength of the men. The scientists explain that the results are well beyond the statistical possibility of chance or coincidence. “The results collected in the study show that there are parameters of the voice that allow to determine the strength and aggressiveness of a person, which do not become clear when looking at photographs. These data indicate that in the course of evolution, people have learned to use this information,” adds the author of the study. However, scientists were unable to figure out exactly which acoustic parameters allow judging the strength and aggressiveness of the owners of one or another voice.