This focus on religion is true for Democratic candidates as well. In the 2008 election, Barack Obama embraced his Christian faith, even as opponents tried to undermine his campaign with claims that he is a practicing Muslim.

In all of this political discussion, none of the politicians are avowed atheists. There is a range of religious affiliations among candidates, but none of them claim to have no belief in God at all.

A paper in the December, 2011 issue of the Journal of and Social Psychology by Will Gervais, Azim Shariff, and Ara Norenzayan helps explain why.

They argue that people are less willing to trust someone who is an atheist than someone who believes in God, and that creates .

First, the authors did a simple survey of over 300 Americans ranging in age from 18-82 from a variety of different backgrounds. They had participants rate their overall liking, level of trust, and level of disgust for people in general, for atheists, and for gay men.

They found that participants felt warmest toward people in general, less warmly toward gay men in general (showing that there is prejudice against gay men) and least warmly toward atheists (showing that there is prejudice against atheists). The other ratings taken found that prejudice against atheists was related to whether they thought atheists were trustworthy. Prejudice against gay men was related to the degree to which participants were disgusted by their behavior.

I want to be clear here. I believe that prejudice against any group is wrong. I am reporting these results to demonstrate that prejudice against atheists and prejudice against gay men have different sources. Prejudice against atheists arises when people think they are untrustworthy. Prejudice against gay men arises when people are disgusted by them.

In another study, the authors used a more indirect approach. They first described an untrustworthy person. This man (named Richard) first bumped his car into someone else's in a parking lot and then pretended to write down his insurance information and sped off. Later, he found a wallet on the ground and took all the money out and tossed the wallet in the trash.

When people were asked if Richard was more likely to be a teacher and a Christian than to be a teacher, they rarely selected the combination of teacher and Christian. The same was true for teacher and Muslim. When asked whether Richard was more likely to be a teacher and a rapist than a teacher, they selected the combination about 40% of the time (much higher than for the other two groups). Strikingly, when asked whether Richard was more likely to be a teacher and an atheist, they selected the combination over 40% of the time. One of the studies in this series went on to demonstrate that this finding occurred, because participants believe that people act in a more trustworthy way when they think that God is watching them.

One last study put people in the position of having to hire a new employee for a job that required a high level of trust (a daycare worker) or a low level of trust (a waitress). People were much less likely to want to hire an atheist for a high trust position than for a low trust position.

Putting all this together, then, it is easy to see why politicians embrace religion. Political office holders are put in the public trust. Polls generally suggest that the public does not have high that politicians are trustworthy. So, a politician running for office cannot start out by professing a belief that will make them look very untrustworthy in people's eyes.

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