Many people derive peace of mind and purpose in life from their belief in God. For others, however, religion provides unsatisfying answers. Are there brain differences between believers and nonbelievers? Here we show that religious conviction is marked by reduced reactivity in the anterior cingulate cortex (ACC), a cortical system that is involved in the experience of anxiety and is important for self-regulation. In two studies, we recorded electroencephalographic neural reactivity in the ACC as participants completed a Stroop task. Results showed that stronger religious zeal and greater belief in God were associated with less firing of the ACC in response to error and with commission of fewer errors. These correlations remained strong even after we controlled for personality and cognitive ability. These results suggest that religious conviction provides a framework for understanding and acting within one's environment, thereby acting as a buffer against anxiety and minimizing the experience of error.
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Their findings show religious belief has a calming effect on its devotees, which makes them less likely to feel anxious about making errors or facing the unknown. But Inzlicht cautions that anxiety is a "double-edged sword" which is at times necessary and helpful. "Obviously, anxiety can be negative because if you have too much, you're paralyzed with fear," he says. "However, it also serves a very useful function in that it alerts us when we're making mistakes. If you don't experience anxiety when you make an error, what impetus do you have to change or improve your behaviour so you don't make the same mistakes again and again?"
These data confirm other results which seem to suggest that theists are more well adjusted and less neurotic than atheists. I would also caution that perhaps there are causal chains here which are confounding our inferences as to the sequence of cause and effect. Atheism is just a weird cognitive phenotype, especially in very religious societies. Also, I think the caution expressed by one of the authors of the paper is well taken. Calm confidence can yield great results, but you probably want civil engineers to be a little paranoid and anxious so that they double check their results.