Distrust is the central motivating factor behind why religious people dislike atheists, according to a new study led by University of British Columbia psychologists.

"Where there are religious majorities -- that is, in most of the world -- atheists are among the least trusted people," says lead author Will Gervais, a doctoral student in UBC's Dept. of Psychology. "With more than half a billion atheists worldwide, this prejudice has the potential to affect a substantial number of people."

While reasons behind antagonism towards atheists have not been fully explored, the study -- published in the current online issue of Journal of Personality and Social Psychology -- is among the first explorations of the social psychological processes underlying anti-atheist sentiments.

"This antipathy is striking, as atheists are not a coherent, visible or powerful social group," says Gervais, who co-authored the study with UBC Associate Prof. Ara Norenzayan and Azim Shariff of the University of Oregon. The study is titled, Do You Believe in Atheists? Distrust is Central to Anti-Atheist Prejudice.

The researchers conducted a series of six studies with 350 American adults and nearly 420 university students in Canada, posing a number of hypothetical questions and scenarios to the groups. In one study, participants found a description of an untrustworthy person to be more representative of atheists than of Christians, Muslims, gay men, feminists or Jewish people. Only rapists were distrusted to a comparable degree.

The researchers concluded that religious believer's distrust -- rather than dislike or disgust -- was the central motivator of prejudice against atheists, adding that these studies offer important clues on how to combat this prejudice.

One motivation for the research was a Gallup poll that found that only 45 per cent of American respondents would vote for a qualified atheist president, says Norenzayan. The figure was the lowest among several hypothetical minority candidates. Poll respondents rated atheists as the group that least agrees with their vision of America, and that they would most disapprove of their children marrying.

The religious behaviors of others may provide believers with important social cues, the researchers say. "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," says Norenzayan. "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."