Why We Believe

It wasn't immediately obvious to Walter Semkiw that he was the reincarnation of John Adams. Adams was a lawyer and rabble-rouser who helped overthrow a government; Semkiw is a doctor who has never so much as challenged a parking ticket. The second president was balding and wore a powdered wig; Semkiw has a full head of hair. But in 1984, a psychic told the then medical resident and psychiatrist-in-training that he is the reincarnation of a major figure of the Revolution, possibly Adams. Once Semkiw got over his skepticism—as a student of the human mind, he was of course familiar with "how people get misled and believe something that might not be true," he recalls—he wasn't going to let superficial dissimilarities dissuade him so easily. As he researched Adams's life, Semkiw began finding many tantalizing details. For instance, Adams described his handwriting as "tight-fisted and concise"—"just like mine," Semkiw realized. He also saw an echo of himself in Adams's dedication to the cause of independence from England. "I can be very passionate," Semkiw says. The details accumulated and, after much deliberation, Semkiw went with his scientific side, dismissing the reincarnation idea.

But one day in 1995, when Semkiw was the medical director for Unocal 76, the oil company, he heard a voice in his head intoning, "Study the life of Adams!" Now he found details much more telling than those silly coincidences he had learned a dozen years earlier. He looked quite a bit like the second president, Semkiw realized. Adams's description of parishioners in church pews as resembling rows of cabbages was "something I would have said," Semkiw realized. "We are both very visual." And surely it was telling that Unocal's slogan was "the spirit of '76." It was all so persuasive, thought Semkiw, who is now a doctor at the Kaiser Permanente Medical Group in California, that as a man of science and reason whose work requires him to critically evaluate empirical evidence, he had to accept that he was Adams reincarnated.

Perhaps you don't believe that Semkiw is the reincarnation of John Adams. Or that playwright August Wilson is the reincarnation of Shakespeare, or George W. Bush the reincarnation of Daniel Morgan, a colonel in the American Revolution who was known for his "awkward speech" and "coarse manners," as Semkiw chronicles on his Web site johnadams.net. But if you don't believe in reincarnation, then the odds are that you have at least felt a ghostly presence behind you in an "empty" house. Or that you have heard loved ones speak to you after they passed away. Or that you have a lucky shirt. Or that you can tell when a certain person is about to text you, or when someone unseen is looking at you. For if you have never had a paranormal experience such as these, and believe in none of the things that science says do not exist except as tricks played on the gullible or—as neuroscientists are now beginning to see—by the normal workings of the mind carried to an extreme, well, then you are in a lonely minority. According to periodic surveys by Gallup and other pollsters, fully 90 percent of Americans say they have experienced such things or believe they exist.

If you take the word "normal" as characteristic of the norm or majority, then it is the superstitious and those who believe in ESP, ghosts and psychic phenomena who are normal. Most scientists and skeptics roll their eyes at such sleight of word, asserting that belief in anything for which there is no empirical evidence is a sign of mental pathology and not normalcy. But a growing number of researchers, in fields such as evolutionary psychology and neurobiology, are taking such beliefs seriously in one important sense: as a window into the workings of the human mind. The studies are an outgrowth of research on religious faith, a (nearly) human universal, and are turning out to be useful for explaining fringe beliefs, too. The emerging consensus is that belief in the supernatural seems to arise from the same mental processes that underlie everyday reasoning and perception. But while the belief in ghosts, past lives, the ability of the mind to move matter and the like originate in normal mental processes, those processes become hijacked and exaggerated, so that the result is, well, Walter Semkiw.

Raised as a Roman Catholic, Semkiw is driven by a what-if optimism. If only people could accept reincarnation, he believes, Iraq's Sunnis and Shiites might stop fighting (since they might be killing someone who was once one of them). He is dismissive of the idea that reincarnation has not been empirically proved. That was the status of everything science has since proved, be it the ability of atoms to vibrate in synchrony (the basis of the laser) or of mold to cure once-lethal infections (penicillin). Dedicated to the empirical method, Semkiw believes the world is on the brink of "a science of spirituality," he says. "I don't know how you can't believe in reincarnation. All it takes is an open mind."

On that, he is in agreement with researchers who study the processes of mind and brain that underlie belief. As scientists began studying belief in the paranormal, it quickly became clear that belief requires an open mind—one not bound by the evidence of the senses, but in which emotions such as hope and despair can trump that evidence. Consider the Tichborne affair. In 1854, Sir Roger Tichborne, age 25, was reported lost at sea off the coast of Brazil. His inconsolable mother refused to accept that her son was dead. Twelve years later a man from Wagga Wagga, in New South Wales, Australia, got in touch with her. He claimed to be Sir Roger, so Lady Tichborne immediately sent him money to sail to England. When the claimant arrived, he turned out to be grossly obese, E.J. Wagner recounts in her 2006 book "The Science of Sherlock Holmes." Sir Roger had been very thin. Sir Roger had had tattoos on his arm. The claimant had none. He did, however, have a birthmark on his torso; Sir Roger had not. Although Sir Roger's eyes had been blue, the claimant's were brown. Lady Tichborne nevertheless joyfully proclaimed the claimant her son and granted him £1,000 per annum. Lawsuits eventually established that the claimant was an impostor.

Letting hope run roughshod over the evidence of your eyes, as Lady Tichborne did, is surprisingly easy to do: the idea that the brain constructs reality from the bottom up, starting with perceptions, is woefully wrong, new research shows. The reason the grieving mother did not "see" the claimant as others did is that the brain's sensory regions, including vision, are at the mercy of higher-order systems, such as those that run attention and emotions. If attention is not engaged, images that land on the retina and zip back to the visual cortex never make it to the next stop in the brain, where they would be processed and identified and examined critically. If Lady Tichborne chose not to focus too much on the claimant's appearance, she effectively blinded herself. Also, there is a constant back-and-forth between cognitive and emotion regions of the brain, neuroimaging studies have shown. That can heighten perception, as when fear sharpens hearing. But it can also override the senses. No wonder the poor woman didn't notice those missing tattoos on the man from Wagga Wagga.