He begins the way he begins every meditation session, lighting candles and jasmine incense before settling into a lotus position. He focuses inward, willing the essence he regards as his true self to break free from his desires, worries and senses. There is a difference this time, though. The young Tibetan Buddhist has a length of twine beside him and an IV in his left arm. As he approaches the transcendent peak of his meditative state, he tugs on the twine. At the other end, in the next room, Dr. Andrew Newberg feels the pull, and quickly injects a radioactive tracer into the IV line. Then Newberg whisks him into a brain-imaging machine called SPECT--and the man's sense of unity with the cosmos gets boiled down to a computer readout. A region at the top rear of the brain which weaves sensory data into a feeling of where the self ends and the rest of the world begins looks like the victim of one of California's rolling blackouts. Deprived of sensory input by the man's inward concentration, this "orientation area" cannot do its job of finding the border between self and world. "The brain had no choice," says Newberg. "It perceived the self to be endless, as one with all of creation. And this felt utterly real."
The tension between science and religion is about to get tenser, for some scientists have decided that religious experience is just too intriguing not to study. Neurologists jumped in first, finding a connection between temporal lobe epilepsy and a sudden interest in religion. As V. S. Ramachandran of the University of California, San Diego, told a 1997 meeting, these patients, during seizures, "say they see God" or feel "a sudden sense of enlightenment." Now researchers are looking at more-common varieties of religious experience. Newberg and the late Dr. Eugene d'Aquili, both of the University of Pennsylvania, have a name for this field: neuro-theology. In a book to be published in April, they conclude that spiritual experiences are the inevitable outcome of brain wiring: "The human brain has been genetically wired to encourage religious beliefs."
Even plain old praying affects the brain in distinctive ways. In SPECT scans of Franciscan nuns at prayer, the Penn team found a quieting of the orientation area, which gave the sisters a tangible sense of proximity to and merging with God. "The absorption of the self into something larger [is] not the result of emotional fabrication or wishful thinking," Newberg and d'Aquili write in "Why God Won't Go Away." It springs, instead, from neurological events, as when the orientation area goes dark.
Neuro-theology also explores how ritual behavior elicits brain states that bring on feelings ranging from mild community to deep spiritual unity. A 1997 study by Japanese researchers showed that repetitive rhythms can drive the brain's hypothalamus, which can bring on either serenity or arousal. That may explain why incantatory hymns can trigger a sense of quietude that believers interpret as spiritual tranquillity and bliss. In contrast, the fast rapturous dancing of Sufi mystics causes hyperarousal, scientists find, which can make participants feel as if they are channeling the energy of the universe. Although the inventors of rituals surely didn't know it at the time, these rites manage to tap into the precise brain mechanisms that tend to make believers interpret perceptions and feelings as evidence of God or, at least, transcendence. Rituals also tend to focus the mind, blocking out sensory perceptions--including those that the orientation area uses to figure out the boundaries of the self. That's why even nonbelievers are often moved by religious ritual. "As long as our brain is wired as it is," says Newberg, "God will not go away."
If brain wiring explains the feelings believers get from prayer and ritual, are spiritual experiences mere creations of our neurons? Neuro-theology at least suggests that spiritual experiences are no more meaningful than, say, the fear the brain is hard-wired to feel in response to a strange noise at night. Believers, of course, have a retort: the brain's wiring may explain religious feelings--but who do you think was the master electrician?