An ad featuring Ron Reagan, son of the Republican former President Ronald Reagan, surprised some viewers of the recent Democratic primary debates.

In the 30-second spot, run by the Freedom from Religion Foundation, Reagan expressed concern that religious beliefs have gained too much political influence in the United States.

Reagan signed off by describing himself as a “lifelong atheist, not afraid of burning in hell.”

Reagan’s detractors expressed alarm. They were concerned that an “unabashed atheist” – a person who lacks belief in a god or gods – could speak so bluntly on national television. And the ad inspired some strong reactions, with some major networks even banning it from the airwaves. And perhaps that should be unsurprising.

Research shows there is intense prejudice against atheists in the U.S. Of the approximately 25% proportion of the U.S. population who do not identify as religious, a little over 3% identify specifically as atheists, although, some researchers claim the actual number might even be as high as 20%.

What’s behind such distrust?

Prejudice toward atheists

Because of this prejudice, people might be reluctant to identify themselves as atheists, even on anonymous questionnaires. Research shows that atheists are trusted less than religious people. In fact, even atheists trust their fellow atheists less than religious people. And until recently, a majority of Americans believed that atheists are not moral. University of Kentucky scholar Will Gervais and colleagues have found that people in several countries even tend to associate serial murder with atheism, relative to religious belief.

Social psychologists have spent years examining what causes some people to have negative feelings, thoughts and behavior toward atheists. Some work argues, for example, that atheists are disliked because they remind religious believers of their inevitable mortality. That is, atheists deny the existence of an afterlife. When reminded of death, this theory suggests, religious people respond with increased prejudice toward atheists.

Our 2018 study on the prejudices that religious believers hold against atheists, conducted along with our colleagues at Arizona State University, examined one previously unexplored cause of atheist prejudice: perceptions of their sexual behavior.

Religious people and values

Evidence suggests that religion and sexual behavior are often linked. Many major religions, such as Christianity, Judaism, Islam and some traditional religions, promote lifestyles emphasizing fidelity and underscoring the importance of caring for one’s family. And a large body of research suggests that such religions may be especially attractive to people who value such commitments – perhaps precisely because those religions help to reinforce their own lifestyle choices.

This is not to say that all sexually committed people are religious or vice versa. Rather, this seems to be a stereotype. For example, many atheists are married, and around 40% have young children.

Still, knowing the perceived connection between faith and sexual commitment, we suspected that people may see atheists, relative to believers, as less likely to endorse values like monogamy and caring for one’s family – values associated with being sexually committed.

In such people’s minds, sexually uncommitted behavior is linked to several other traits and social behavior, such as opportunism and being impulsive – traits that hardly inspire trust. So we reasoned that people’s stereotypes of atheists as being sexually uncommitted were the root cause of distrust of atheists.

Distrust of uncommitted partners?

To test this, we recruited 336 participants from the U.S. to complete an online experiment. They were randomly assigned to rate one of two detailed dating profiles. These two profiles differed only in whether the person profiled identified as religious or nonreligious.

We found that participants made inferences about the person in the profile based solely on religiosity. First, and consistent with past research, the nonreligious person was trusted less than the religious person.

Second, supporting our theory, the nonreligious person was rated as less likely to have committed lifestyle. For example, compared to the religious profile, people viewed the nonreligious one as less of a “faithful romantic partner” and less of a “dedicated” parent.

To determine whether this inference that atheists are sexually uncommitted actually caused distrust, we conducted a second experiment. We recruited 445 U.S. participants and showed them the same profiles, but with one additional piece of information: The person in the profile was also described as keen to either “get married” or “play the field.”

Adding this scant bit of information about sexual behavior – “dating preferences” – was enough to override the assumptions people made about atheists. Atheists who wanted to “get married” were thought to be just as trustworthy as religious people, and they were thought to be even more trustworthy than religious people who wanted to “play the field.”

Statistically, a person’s dating preferences explained approximately 19.7% of participants’ trustworthiness ratings – a fairly large effect for social sciences. By contrast, the person’s religiosity explained less than 1%.

Notably, religious participants did not evaluate the religious profile more favorably, suggesting that even religious folks are swayed more by someone’s sexual behavior than that person’s religiosity.