As to what’s going on in their brains, Newberg says, “It depends to some degree on what the practice is.” Practices that involve concentrating on something over and over again, either through prayer or a mantra-based meditation, tend to activate the frontal lobes, the areas chiefly responsible for directing attention, modulating behavior, and expressing language.

Dr. Andrew Newberg/The Atlantic

In contrast, when practitioners surrender their will, such as when they speak in tongues or function as a medium, activity decreases in their frontal lobes and increases in their thalamus, the tiny brain structure that regulates the flow of incoming sensory information to many parts of the brain. This suggests that their speech is being generated from some place other than the normal speech centers.

Dr. Andrew Newberg/The Atlantic

Believers could say this proves that another entity is speaking through the practitioner, while nonbelievers would look for a neurological explanation. Newberg takes into account both perspectives. When he defines neurotheology in his book, Principles of Neurotheology, he writes, “An ardent atheist, who refuses to accept any aspect of religion as possibly correct or useful, or a devout religious person, who refuses to accept science as providing any value regarding knowledge of the world, would most likely not be considered a neurotheologian.”

Newberg believes everyone can benefit from some type of meditation practice. If one practice isn’t working for an individual, she should try something else. As a general rule, these practices lower depression, anxiety, and stress. He adds that at Thomas Jefferson University in Philadelphia, where he is director of research at the Myrna Brind Center of Integrative Medicine, researchers have found that meditation can improve memory and concentration.

It’s debatable whether these practices are more effective when founded on religious or spiritual beliefs. Dr. Dean Hamer, author of the book, The God Gene: How Faith is Hardwired into our Genes, discovered that research subjects with a particular variation of a certain gene were more susceptible to self-transcendent, spiritual experiences.

In a lecture given at Marlboro College titled, “Gays, God, and Genes,” Hamer compares the effects of this variation to an enhanced capacity for natural highs. This spiritual tendency also depends on a person’s environment, according to Hamer, which can direct their innate spirituality to particular religious beliefs, and/or steer them away from religion altogether. He says that science will never replace spirituality because a reliance on facts will never have the same emotional appeal.

Newberg agrees that spiritual beliefs are influenced by a person’s genetics and environment, and that meditation practices are more effective when they reinforce a practitioner’s belief system. However, he says researchers are still investigating whether religious beliefs in general make healthier and happier people. He considers atheism to be a belief system as well, and says that a possible a mental health benefit of belonging to a religious denomination could be not just belief, but the built-in social network.