Besides the face, which is the first thing you notice on a newly met person? It's his/her voice. Apart from the face or facial expression, the voice is the most important signal whether the person is friend or foe, bland or tough, hot or disgusting.
And the physical appearance may offer clues to his/her sexuality.
"Voice is a profound difference between men and women, and it colors every human interaction we have," said David Puts, an anthropologist at Michigan State University.
He made a study revealing that men with deeper voices had more luck with women. The main difference between male and female voices is pitch: men, on average, speak with an octave lower than women.
But it's even harder to say what makes a woman's voice attractive to men. It is said that men prefer high-pitched female voices, but there's no study made on this and many men complain that a too high one, when the voice turns from sweet into shrill, is annoying.
In fact, men don't find high voices sexy; a deep and sultry voice like that of Marylin Monroe is what turns them on.
"We might think of (Kathleen) Turner's voice as deep, what actually characterizes it is breathiness. Breathiness comes from air whistling through a gap at the back of the vocal cords. The gap is larger in women, giving them a breathier voice. Men might find a super-breathy voice sexy because it accentuates this naturally female trait," said Harvard psychologist David Feinberg.
"Men tend to agree strongly about which voices are attractive. But, men have trouble pinpointing exactly what makes them swoon," said psychologist Susan Hughes of Albright College.
Hughes focused on "formant dispersion". We regularly hit on different frequencies while we speak. Formant dispersion refers to whether our usual frequencies are spaced closely together (a shrill or monotone voice) or far apart (an NPR host). The broader the range, the "fuller" the voices.
But how do fullness, breathiness and pitch combine to deliver a sexy female voice?
"There's a mysterious vocal quality that men seem to recognize by ear but that is tough to identify using computer programs alone. What's even stranger is that both men and women with sexy voices also tend to be more symmetrical and have traditionally sexy body types: the men in my studies tended to have broad shoulders and narrow hips, and the women tended to have hourglass-shaped figures." said Hughes.
"In men, these differences could be chalked up to testosterone. During puberty, testosterone helps boys build broad shoulders and big muscles. It also helps lower their voice. Sex hormones may also account for a woman's sexy voice and curvy figure," she added.
As voice development is linked to sex hormones, it reveals sexual maturity, easing the find of a mate for reproduction. A deep male voice acted like a testosterone advertisement. Hughes also found that people with attractive voices tend to have more sex partners over their lifetimes.
"They're chosen as affair partners more often, and they'll lose their virginity at an earlier age." said Hughes.
Perhaps the hormones that induced the sexy voice also mean high sex drive, or the sexiness of the voice attracts more partners. In the end, Barry White was called "The Walrus of Love", while Chris Tucker...hmmmm.... Let's forget it ...