Humans perceive a person's attractiveness based on vocal qualities that suggest the voice belongs to a person of "relatively small body size," according to a study released Wednesday.
Participants in the study, done by researchers at University College London, listened to altered vocal patterns of a person saying "good luck on your exams" and were asked to judge a person's perceived attractiveness.
Female voices that rated attractive to men "were breathy, high pitched (though not too high) … and consistent with the projection of a relatively small body size."
Male voices that rated attractive to women "were low pitched," which suggests a large body size. But female participants said that "male voice attractiveness also increase[s] with breathiness, which projects a small body size."
Yi Xu, lead author of the study, says the finding suggests that women may have evolved to be attracted to men who are not overly aggressive.
"The breathiness softens the aggressiveness associated with a large body size projected by low pitch in an attractive male voice," he says. "In other words, females prefer a male that is both masculine and tender."
Previous studies have suggested that when people hear a voice, they believe they can guess a person's body size. But in reality, Xu says, "actual body size is not well related to [voice]."
The study was published in the journal PLOS ONE.