New research finds exposure to Christian ideas—or even standing in the shadow of a cathedral—nudges people in the direction of black-and-white thinking.

Pope's chair, Basilica di San Giovanni in Laterano, Roma, Italy. (PHOTO: ERN/WIKIMEDIA COMMONS)

It’s clear that religious faith confers a variety of benefits. Being part of a community of fellow believers has been shown to boost both mental and physical health.

But at what cost? New research suggests one disturbing answer: Thoughts of faith and God apparently spur people to view the world in black-or-white terms.

A just-published study finds exposure to Christian concepts or imagery increases one’s intolerance for ambiguity. This dynamic was demonstrated in a variety of experiments conducted in three different countries: Germany, Austria, and the United States.

Writing in the Journal of Experimental Social Psychology, psychologists Christina Sagioglou of the University of Innsbruck and Matthias Forstmann of the University of Cologne note that “one prototypical characteristic of Christian morality seems to be the two-tier distinction between ‘virtuous’ and ‘sinful’ behaviors.”

A new study finds exposure to Christian concepts or imagery increases one’s intolerance for ambiguity. This dynamic was demonstrated in a variety of experiments in three different countries.

With that in mind, the researchers reasoned that exposing people to Christian content would “shift a person’s cognitive style” so that he or she thinks in more dualistic terms, and is less comfortable with ambiguity. They present evidence supporting their theory in the form of five experiments.

The first featured 65 participants recruited from Amazon’s Mechanical Turk. “Ostensibly to assess word comprehension,” they began by unscrambling 10 sets of words to form simple sentences. For half of the participants, five of the sets contained religion-related words such as faith, church, heaven, prayer, and divine.

Afterwards, they completed a 20-item survey designed to measure tolerance for ambiguity. Participants were asked their level of agreement with such statements as “There is a right way and a wrong way to do almost everything” and “It bothers me when I am unable to follow another person’s train of thought.” Finally, they answered five questions measuring their underlying level of religiosity.

Those who had worked with the religion-related words reported greater discomfort with ambiguity. They also generally perceived less ambiguity, in that they were more likely to agree with statements such as “practically every solution has a problem.”

Among those who did not unscramble sentences containing religious words, higher levels of religiousness “significantly correlated with ambiguity intolerance,” the researchers add. This suggests a black-or-white attitude is intrinsic to the mindset of the very religious, while for others, it can be triggered by exposure to religious concepts.

A second experiment, featuring 49 participants, found this dynamic also held true for visual stimuli. After they unscrambled either religion-related or neutral sentences, as above, participants were shown “two black-and-white pencil drawings of female faces: one ambiguous, the other non-ambiguous.” They then rated how much they liked each, on a one-to-seven scale.

The straightforward drawing featured the face of a young woman, seen clearly from the front. The ambiguous drawing can be interpreted in one of two ways: as a depiction of a young woman, as seen from behind and slightly to one side, or an image of an older woman seen in profile. Neither drawing contained any references to religion.

Those with religious concepts on their mind “liked the ambiguous drawing significantly less,” the researchers report. “Participants primed with religion clearly preferred the non-ambiguous drawing to the ambiguous one.”

Perhaps the most striking experiment featured 81 people who were approached at one of two central locations in Innsbruck, Austria: the cathedral square, or a square surrounded by civic buildings. They filled out a questionnaire measuring their tolerance for ambiguity, and their underlying religiosity.

The results: While there was no difference in religiosity between the two groups, “participants approached at the cathedral indeed reported significantly more ambiguity intolerance than did participants approached at the civic square,” the researchers report.

This echoes earlier research that Americans whose polling place is a church are more likely to support candidates and causes supported by the religious right. The looming presence of religious iconography is apparently enough to influence at least some people’s feelings and perceptions.

One obvious question raised by this study is whether this effect is specific to Christianity. Sagioglou and Forstmann doubt it, noting that a 1981 study found a correlation between ambiguity intolerance and religiosity among Indian Muslims and Hindus. If their thesis is right, any faith that divides people or actions into “good” and “bad” will presumably have the same effect.

It’s worth noting that some experts on Christian ethics, such as Harvey Cox in his sophisticated analysis of Jesus’ parables, find a great deal of nuance. But this research suggests that, in most people’s minds, religion is linked with moral rigidity.

As the researchers write, this attitude no doubt gives people structure in their lives and contributes to their well-being. But it’s also a plausible route to prejudice and general close-mindedness.

Perhaps it’s no coincidence that the television drama that best dramatizes ethical gray areas, The Good Wife, is also one of the very few in which the lead character is an atheist.