THURSDAY, March 15 (HealthDay News) -- Politicians may want to keep the pitch of their voice low when asking for votes, because people appear to prefer candidates with deep voices, scientists have found.

The study included dozens of men and women who listened to recordings of high- and low-pitched voices saying, "I urge you to vote for me this November."

Both the male and female participants "elected" the candidates with the lower-pitched voices, regardless of the speaker's gender.

The findings suggest that biology -- not just political beliefs -- can affect voters' choices, according to the study published March 14 in the journal Proceedings of the Royal Society B.

"We often make snap judgments about candidates without full knowledge of their policies or positions. These findings might help explain why," Rindy Anderson, a biologist at Duke University, said in a university news release.

"It's clear that our voices carry more information than the words we speak," she said. "Knowing this can help us understand the factors that influence our social interactions and possibly why there are fewer women elected to high-level political positions."

The study is an "interesting first step toward understanding the psychological mechanisms that affect voters' choices," Brad Verhulst, a researcher at Virginia Commonwealth University in Richmond, said in the news release. He was not involved in the study.

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Visit the American Academy of Otolaryngology -- Head and Neck Surgery for more about how the voice works.