If an atheist ran for president, a recent poll suggests, he or she wouldn't win many votes.

That might be at least partly because of the main reason religious people dislike atheists: They think nonbelievers can't be trusted, according to a new study.

"Where there are religious majorities - that is, in most of the world - atheists are among the least trusted people," said the study's lead author, Will M. Gervais, a doctoral student at the University of British Columbia, in a press release from the University of Oregon, where a co-author is an assistant professor.  The research was published in the Journal of Personality and Social Psychology.

In six separate studies, the researchers asked 770 people - American adults and Canadian college students - a number of questions.  In one study, when presented with a description of an untrustworthy person, participants said they believed that description represented atheists and rapists to a similar degree and wasn't as representative of gays, feminists, Christians, Jews or Muslims.

Another co-author, the University of British Columbia's Ara Norenzayan, said one of the reasons for doing the study was a recent poll that found that only 45 percent of Americans who responded would vote for an atheist presidential candidate.  Those who were polled said atheists least represented their vision of America.

"Outward displays of belief in God may be viewed as a proxy for trustworthiness, particularly by religious believers who think that people behave better if they feel that God is watching them," Norenzayan said in the news release. "While atheists may see their disbelief as a private matter on a metaphysical issue, believers may consider atheists' absence of belief as a public threat to cooperation and honesty."

Atheists also tend to trust religious people more than they trust other atheists.

"Those people who did not identify with a religion still tended to find believers to be more trustworthy," said the third co-author, Azim Shariff of the University of Oregon.

That's because people trust "those who fear supernatural punishment," Shariff added, and because atheists aren't especially vocal, powerful or connected.

Despite that, the study authors said these feelings toward atheists could be far-reaching.

"With more than half a billion atheists worldwide, this prejudice has the potential to affect a substantial number of people," Gervais said.