While deeper male voices have often been thought to be more attractive to straight women, a new study published in Proceedings of the Royal Society B suggests that this may not be the main purpose of the evolutionary trait. Recent research from Penn State University finds that men have deeper voices not to attract the opposite sex but rather to display dominance to other men.

That's right, ladies: That deep, rumbling bass wasn't pitched for sex appeal. It evolved to intimidate male competition, at least according to lead researcher David Puts, an anthropologist affiliated with the university.

By comparing vocalizations of different primates — among whom humans have the biggest sex-based difference —scientists looked to see if the pitch of male voices could be correlated to mating behavior. Rather than influencing sexual attraction, the pitch of men's voices seemed to have evolved to threaten other men, researchers found. Voice pitch seems to affect the way that women viewed deeper voiced males only slightly.

How do we know?

To test the theory, the team recorded more than 500 men and women speaking, playing the recordings back to more than 1,100 different men and women. Male voice recordings were rated by men for dominance and by women for short- and long-term romantic attractiveness. (Male recordings were not rating by other men for attractiveness.)

Lower voices were consistently rated as more dominant by other men. Meanwhile, women were inconsistent in finding lower-pitched voices more attractive.

Researchers believe this makes sense, because deeper-voiced men were less likely to have high levels of cortisol and more likely to have high levels of testosterone, according to the study. Since cortisol is a stress hormone that tends to damage overall health, Puts suggests that this data tells us something about the state of men with lower voices.

"It tell us ... about their condition, their health, their formidability," Puts said.

Female voices were also rated by men for attractiveness in the study, but the findings were inconclusive, which may point to why women seem to do fine in the dating marketplace regardless of voice pitch.

So it's really not about sex appeal?

"We find that masculine traits in humans are not the same as, say, in peacocks, where the beautiful tail attracts a mate," Puts said in a release from Penn State. "For example, beards make men more dominant-looking, scarier, and seemingly more dangerous, but most women prefer clean-shaven men."

Puts explains that some species have easier-to-decipher sex distinctions that seem to help the opposite sex to choose a mate, but that female humans do not choose their partners in easily predictable ways. His team acknowledges that lower-pitched voices do make men more attractive to women in some cases, but the research suggests that other men were actually the strongest reactors to deeper male voices.

According to Puts, "A lower pitch made men attractive to women. But it especially made men seem more dominant to other men."

An extremely deep voice might even be a negative attribute, at least when it comes to finding a romantic partner. Previous studies suggest that women perceive men with very deep voices as more likely to cheat on them. Puts also writes that his research shows that women tend to prefer voices that are deeper than the male average, but not too deep or too high. Like Goldilocks and the three bears, there's a happy medium that's statistically just right.