Why are some people more religious than others? Answers to this question often focus on the role of culture or upbringing. Although these influences are important, new research suggests that whether we believe or not may also have to do with how much we rely on intuition versus analytic thinking. In 2011 researchers from Harvard University published a paper showing that people who have a tendency to rely on their intuition are more likely to believe in God. They also showed that encouraging people to think intuitively increased people's belief in God.

Building on these results in an article published in Science recently, Will Gervais and Ara Norenzayan of the University of British Columbia found that encouraging people to think analytically reduced their tendency to believe in God. Taken together, these findings suggest belief may stem at least in part from our thinking styles.

Gervais and Norenzayan's research is based on the idea that we possess two different ways of thinking that are related. Understanding these two ways, which are often referred to as system 1 and system 2, may be important for understanding our tendency toward having religious faith. System 1 thinking relies on shortcuts and rules of thumb, whereas system 2 relies on analytic thinking and tends to be slower and to require more effort. Solving logical and analytic problems may require that we override our system 1 thinking processes to engage system 2. Psychologists have developed a number of clever techniques that spur us to do this. Using some of these techniques, Gervais and Norenzayan examined whether engaging system 2 leads people away from believing in God and religion.

In one activity, Gervais and Norenzayan gave participants sets of five randomly arranged words (such as “high winds the flies plane”) and asked them to drop one word and rearrange the others to construct a more meaningful sentence (such as “the plane flies high”). Those participants who unscrambled sentences that contained words related to analytical thinking (such as “reason” or “ponder”) were less likely to express agreement with the statement that God exists. People's prior belief in whether God exists, as measured several weeks before the study took place, was found to be unrelated to the results.

In another experiment, the investigators used an even more subtle way of activating analytic thinking: by having participants fill out a survey measuring their religious beliefs that was printed either in a clear font or in one that was difficult to read. Prior research has shown that a difficult-to-read font promotes analytic thinking by forcing volunteers to slow down and deliberate more carefully about the meaning of what they are reading. The researchers found that participants who completed a survey that was printed in an unclear font expressed less belief as compared with those who filled out the same survey in the clear font.

These studies demonstrate yet another way in which our thinking tendencies, many of which may be innate, have contributed to religious faith. It may also help explain why the vast majority of Americans tend to believe in God. Because system 2 thinking requires effort, most of us tend to rely on our system 1 thinking processes whenever possible.

COMMENT AT ScientificAmerican.com/jul2012