Psychologists have always been fascinated as to why some people believe in a higher being, while others are happy to accept that we are alone in life. Now researchers claim they have found a region of the brain that, when damaged, may increase the likelihood that a person will hold fundamental religious beliefs. In particular, they found that damage to this region reduced cognitive flexibility – the ability to challenge one’s preexisting beliefs when presented with new evidence.

The research builds on previous work that has found a neurological underpinning for religion, particularly in the prefrontal cortex. The study, published in the journal Neuropsychologia, utilized a data set that was initially started to study Vietnam War veterans who had experienced trauma. Using this registry, the team compared soldiers who had received penetrating brain injury with veterans who had not.

They looked at 119 combat veterans with brain damage to their dorsolateral prefrontal cortex. They found that among those studied, the veterans with damage to this region of the brain, which has been linked to planning and problem solving, were less open to new ideas. This may help explain why they were more likely to be fundamental in their religious beliefs.

For the study, they gave the participants tests to see how cognitively flexible they were and placed them on a standardized measure to assess their level of religious fundamentalism. They then took CT scans to measure the size and location of the brain lesions in the veterans. It turned out that those who had received trauma to the dorsolateral prefrontal cortex, a region found at the front of the brain, were more likely to hold fundamental beliefs and were less likely to be cognitively flexible.

“These findings indicate that cognitive flexibility and openness are necessary for flexible and adaptive religious commitment, and that such diversity of religious thought is dependent on [dorsolateral prefrontal cortex] functionality,” write the authors.

Previous experiments have found that this part of the brain is involved in working memory, in which you hold in mind multiple pieces of information you have just learned. It has also been shown to be key to cognitive flexibility. This latest study, the researchers suggests, shows that the dorsolateral prefrontal cortex may also be crucial in helping us remain open about new ideas that may challenge deeply held beliefs.

This does not mean that forming a religious belief is down to some form of brain damage, or that trauma to the head will therefore lead to fundamentalism. The researchers simply state that damage to this particular part of the brain may make it more difficult for a person to assess their own deep-seated beliefs when presented with new evidence.