Men cannot intentionally make their voices sound more sexy or attractive, while women have little trouble doing so, a new study has found.
Researchers from Albright College in US found that women can manipulate their voice to attract a mate by lowering their pitch and increasing their hoarseness.
"This ability may be due to culture and cuts across cultures and time," said Susan Hughes, associate professor of psychology at Albright College.
"There is a stereotype of what is a sexual voice in our culture - a low, breathy voice," Hughes said.
The research examined the patterns that emerge when men and women intentionally modify their voices to project four traits related to mate selection and competition - sexiness, dominance, intelligence and confidence - and how others perceive these manipulations.
For the study, 40 participants (20 men, 20 women) provided intentionally manipulated voice samples for the desired traits, plus a normal speech sample.
Each sample consisted of participants counting from one to 10. Another 40 people assessed the degree to which each sample effectively projected the given trait.
The researchers found that women could make their voices sound more attractive, but men could not.
"In fact, although not significantly, it got a bit worse when men tried to sound sexy," said Hughes.
The difference may be rooted in mate selection, the study said.
Women know that men place greater emphasis on attractiveness when choosing a partner, and that voice attractiveness can predict physical attractiveness.
Thus, it is beneficial for women to sound sexier to enhance their value to potential mates and to stave off competition from rival females.
Spectrogram analyses of the samples showed that both sexes slowed their speech to sound sexy/attractive, while women also lowered their pitch and increased their hoarseness.
Ironically, men prefer higher-pitch females, but a woman will signal her interest in a man by intentionally dropping her voice, said Hughes.
The study found that both sexes can manipulate their voices to sound more intelligent. Women, however, could not sound more confident. Men could, but only when judged by female raters.
This may be true, researchers said, because it's important for men to project confidence to women (and for women to perceive it), since confidence can indicate financial and personal success, which women value in a potential partner.
However, both men and women could equally and effectively manipulate their voices to sound more dominant.
The findings appear in Journal of Nonverbal Behavior.