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.
Spectrogram analyses of the samples revealed 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.
Susan Hughes, Ph.D., associate professor of psychology at Albright College, said that the stereotyped low, breathy voice is considered sexual, and the ability may be due to culture and cuts across cultures and time.
The research examines 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.
The study also found that though both sexes can manipulate their voices to sound more intelligent, but women, could not sound more confident. Men, on the other hand, may be more attuned to detecting male posturing and more inclined to underrate their competition.
The study has been published in the Journal of Nonverbal Behavior.