updated 7/11/2012 7:17:35 AM ET 2012-07-11T11:17:35

When pushed to think in a more rational way, people experience a dip in their religious beliefs, found a new study. Simply looking at pictures of Rodin's sculpture "The Thinker," for example, was enough to make people less likely to agree with statements like, "Nothing is as important to me as serving God as best I know how."

The effects were subtle, and encouraging critical thought is unlikely to destroy anyone's faith. But the findings suggest that rational analysis interacts with gut instinct in the brain to help distinguish between people who believe fully in God and those who abandon religion.

"This could help people take a broader approach to debates about whether religion is true or not, and realize that subtle cognitive differences might be influencing where people end up on that debate," said Will Gervais, a social psychologist at the University of British Columbia, Vancouver, who added that understanding why some people are more religious than others doesn't say anything about who's right.

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Nor is rational thinking the only factor that influences religious belief.

"It's not the case that the Pope walked into the lab and Richard Dawkins walked out," he said. "I think this study tells us one factor that is implicated in whether or not people are believers, but it is just one factor out of many."

While most of the world's population believes in God or gods, hundreds of millions of people do not. To explain how intelligent people might believe in concepts that lack proof, researchers have previously theorized that our brains have two distinct modes of thought. One uses rational analysis to think things through. The other relies on intuition to form beliefs and gut feelings.

With that theory in mind, Gervais and colleague Ara Norenzayan challenged a diverse group of people to answer three questions whose answers were likely to differ depending on whether they reasoned out the answer or went with their gut.

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For example, one question asked, "A bat and a ball cost $1.10 in total. The bat costs $1.00 more than the ball. How much does the ball cost?" Without thinking, many people guess 10 cents, even though a little bit of quick math shows that the correct answer is five.

People in the experiment who stepped back and thought analytically before answering tended to hold weaker religious beliefs, the researchers report today in the journal Science, suggesting a connection between rational thinking and a lack of faith.

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But does the tendency to think rationally cause religious doubt, or does it go the other way? To find out, the researchers conducted a series of experiments with hundreds of people that triggered them to think analytically before answering faith-themed questions about things like their belief in God and the role that faith plays in their decision-making.

In one experiment, participants looked at artwork portraying either a thinker or a man throwing a discus. In another, in which people rearranged letters and words to form sentences, they saw either thinking-related words or neutral words. Yet another experiment asked people to read the religious-beliefs survey in a font that was either easy or hard to decipher.

No matter how the researchers primed the brain to think critically, people's responses were less strongly religious compared to the responses of people who were not put in a rational frame of mind. The findings, Gervais said, suggest that the rational brain is capable of undermining the intuitive brain in slight ways when it comes to faith.

Because our minds and bodies are so closely connected, it's not surprising that religious thought is linked with certain kinds of brain activities, said John Hare, a philosophical theologian at Yale Divinity School in New Haven, Conn. But discoveries like these say nothing about the existence of God or anything else that is outside of the mind.

"For most people of faith, their faith is not a matter of proof," Hare said. "This is true even though throughout the history of the Abrahamic faiths, some of the brightest thinkers have been people of faith, and have proposed proofs of various kinds.

"Probably it is good that there should be a division of labor. Some people can spend their time and efforts reflecting about their faith intellectually. And most people can just live it."

© 2012 Discovery Channel


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