Voice is a major factor in seduction, not just preening, subtle flirting or coy eye contact.
Lowering voice may be means of signaling attraction, Susan Hughes, assistant professor of psychology at Albright College in Reading, Pa, found in the study.
We found that both sexes used a lower-pitch voice and showed a higher level of physiological arousal when speaking to a more attractive opposite-sex target," she said.
The study examined 48 Albright students using Skype to leave scripted voice-messages while viewing a picture of a fictitious person "receiving" the message. The men and women the participants looked at varied in attractiveness.
Hughes - who expected that women would raise their voices to sound more feminine and attractive - was surprised.
"There appears to be a common stereotype in our culture that deems a sexy female voice as one that sounds husky, breathy, and lower-pitched," she said.
"This suggests that the motivation to display a sexy/seductive female voice may conflict with the motivation to sound more feminine," she added.
Female voice manipulation suggests that altering their tone may be a learned behavior based on sexual voice stereotypes rather than actual vocal characteristics of attractiveness.
"When a woman naturally lowers her voice, it may be perceived as her attempt to sound more seductive or attractive, and therefore serves as a signal of her romantic interest," she said.
The study is to be published in the fall by the Journal of Nonverbal Behavior.