Presidential hopefuls vying for the GOP nomination take note.

Political experience, showmanship and donor funding helps, but presidential candidates may have a previously-unknown influence on voters: a low-pitched voice.

Canadian researchers found that potential voters typically said they would be more inclined to vote for a U.S. presidential candidate with a lower-pitched voice.

People think we want to vote for men with lower-pitched voices because they're more attractive, said David Feinberg, psychology professor at McMaster University in Hamilton, Ontario, who supervised the research. But it's because people perceive them as better leaders and more dominant, not just because they're attractive.

The experiment did not test random candidates, but previous U.S. presidents whose voices researchers manipulated to have either higher or lower pitches.

In all cases, the cast votes went to the lower-pitched candidate, whether during peacetime or wartime. The research subjects rated bass-voiced candidates as higher in attractiveness, leadership potential, honesty, intelligence and dominance, the researchers found.

The journal Evolution and Human Behavior published the research online Monday.

The research jives with a study that found U.S. presidential candidates with the lowest pitched voice between 1960 and 2000 won the popular vote.

Throughout our evolutionary history, it would have been important for our ancestors to pay attention to cues to good leadership, because group leaders affected a person's ability to survive and reproduce within a group, Cara Tigue, lead author and graduate student, said. We're looking at it in a present-day, 21st-century context.

Future projects will include Canadian politicians and female politicians, Feinberg said.