The Atheist Spot

Tom Rees

What happens to the soul when the brain is split in half? Well, if you define the soul as a person’s essential personality, then science can give an answer. Remarkably, patients whose brain hemispheres have been surgically separated act as though they have two separate consciousnesses residing in the same body. What’s more, it seems that they can develop opposing beliefs in God. V.S. Ramachandran, director of the Center for Brain and Cognition at the University of California at San Diego, recounts one experiment in which a patient was asked to answer the question “Do you believe in God?” in writing. The right arm, controlled by the left brain, answered no. The right brain, however, disagreed. The right brain believed in God.

Spurred by this finding, some ten years ago Ramachandran surveyed a group of patients who suffered from right temporal lobe epilepsy. It turned out that they also had stronger responses to religious words than nonreligious people, non-epileptic people, and non-epileptic religious people. Going a step further, Michael Persinger of Canada’s Laurentian University managed to induce religious experiences in his subjects by stimulating the right side of the brain with powerful magnets (specifically, the parieto-temporal region, which is toward the back of the head, above the ears)—although, rather famously, Richard Dawkins proved to be immune to his efforts. At the time, journalists (although not Ramachandran himself) triumphantly announced that “the God spot” had been discovered! Scientists had at last found the region of the brain that allows us to commune with God—or so it seemed at the time.

Jump forward a decade, however, and the picture has become much more complicated. Studies using sophisticated brain scanners, which are able to reveal the parts of the brain that become active when a subject thinks about religion, show that many regions of the brain are involved in religious thought. What’s more, the brain regions used for religious thinking are basically the same as those used for the equivalent secular thoughts. For example, studies by Uffe Schjødt at Aarhus University in Denmark have shown that when Lutherans engage in personal prayer, they use the same regions of the brain as they would when talking to a good friend.

Other studies, however, find differences between the brains of believers and nonbelievers. Some of the most intriguing findings result from close examination of people who have suffered some kind of brain damage. Such work has a long tradition in the neurological sciences. By making a careful note of the regions damaged and looking to see how behavior is affected, it’s possible to piece together the function of the damaged region.

One particularly dramatic condition is called “right temporal lobe atrophy,” a rare condition in which a major part of the right side of the brain simply withers away. It’s harder to spot than you might imagine: people with this condition continue to talk normally and often still have use of their dominant hand (for most people, this is the right hand, controlled by the unaffected left brain). They do, however, have a raft of deep-seated psychological problems, as Dennis Chan, a neurologist at the UCL Institute of Neurology in London, discovered earlier this year. These patients get lost easily, find it difficult to recognize faces, and have a variety of behavioral disorders, including disinhibition and various obsessions. One patient insisted on having all the light switches in her house painted gold and silver. Among twenty patients with right temporal lobe atrophy, Chan found three who were hyperreligious, compared with none in the group suffering from left temporal lobe atrophy. Two patients with right temporal lobe atrophy also had “complex visual hallucinations of inanimate objects,” and two had sensory crossover, in which stimulation of one sense was experienced by a different sense.

These are intriguing hints suggesting that damage to the right brain can generate the kinds of visions often associated with religion. Other studies, of patients with more localized damage, offer greater precision. When Brick Johnstone and Bret Glass at the University of Missouri interviewed a group of people with modest traumatic brain injury (they were all walking wounded, able to function in the outside world), they found that damage to the left side of the brain did not seem to affect religious beliefs in any way. However, those with damage to the right side of the brain—specifically the right parietal lobe—reported greater feelings of spirituality compared with people without damage in this area.

In another study, Cosimo Urgesi at Italy’s University of Udine examined the transcendental feelings of patients who had undergone surgery for a brain tumor. This surgery inevitably causes some brain damage in the region of the tumor. Urgesi and his colleagues found that surgery in either the right or the left parietal lobe had the peculiar effect of generating a sensation of transcendence in their subjects. Intriguingly, they found that subjects with tumors in these areas also reported being more religious—even before the surgery!

There’s a telling link between these effects of damage to the right parietal lobe and previous studies looking at brain activity in Buddhist monks. SPECT scans were performed on these Tibetan monks while they were deep in meditation, and Andy Newberg, the author of several books on the neurology of religious experience, discovered that activity in their parietal lobes was quelled—suggesting that switching off this part of the brain is critical to the transcendental experience.

From a neuropsychological perspective, the right hemisphere allows for individuals to define themselves in relation to the immediate environment: the here and now. The right parietal lobe is generally associated with awareness of the self relative to other objects in space, awareness of the self as perceived by others in social situations, and the ability to critically evaluate one’s own strengths and weaknesses (as in the case of insight). Disorders of the right hemisphere involve a diminished capacity in the ability of the self to function in the immediate environment, including difficulties localizing the body in space.

It’s this bit of the brain that figures out where you are in time and space and how you fit into the world around you. If it breaks down, you’ll experience some pretty freaky sensations—which, if the cultural setting is right, the rest of your brain will interpret as a spiritual or even religious experience. Intact, you remain grounded in the real world. In other words, what we have here is not a “God spot,” but rather its opposite—the “atheist spot”!

Tom Rees

Tom Rees is a medical writer and a lifelong humanist. His blog, Epiphenom, covers the latest research into the psychology and social science of religion and nonbelief.

What happens to the soul when the brain is split in half? Well, if you define the soul as a person’s essential personality, then science can give an answer. Remarkably, patients whose brain hemispheres have been surgically separated act as though they have two separate consciousnesses residing in the same body. What’s more, it seems …

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