Like millions of others who believed there must be more to life than the libertine exuberance of the '60s, the Beatles hoped that the Hindu teacher Mahesh Yogi—known as the Maharishi, or "great saint"—would help them "fill some kind of hole," as Paul McCartney put it years later. So in the spring of 1968, the Fab Four traveled to the Maharishi's ashram overlooking the Ganges River in northern India, where they meditated for hours each day in search of enlightenment, as Bob Spitz recounts in his exhaustive 2005 biography, "The Beatles." The high-profile visit still echoes 40 years later—in, of all places, science, for the trip popularized the notion that the spiritual East has something to teach the rational West. Soon the Maharishi was on Time magazine next to the line "Meditation: The Answer to All Your Problems?"

It wasn't. But in the late 1960s a few intrepid scientists began dipping their toes into the exotic new waters to study the effects of Transcendental Meditation (TM), which the Maharishi developed, and other forms of mental training. Most of that early research "was just not of high caliber," says B. Alan Wallace, president of the Santa Barbara Institute of Consciousness Studies. "Reputable scientists were told, 'We can't study that; we'll be tarred and feathered'." But just as meditation has become as mainstream as aerobics, research on it has achieved a respectability that astonishes those who remember the early floundering. With neuroscientists at the University of California, Davis, Wallace is leading a $1.4 million study of the effects of intensive meditation on attention, cognitive function and emotion regulation. Prestigious institutions such as the M.D. Anderson Cancer Center conduct studies on how Tibetan yoga improves sleep in patients with lymphoma, and top journals publish research on the brain waves of Buddhist monks. Studies of meditation are more than mainstream. They're expanding beyond the predictable—I mean, how surprising is it that meditating lowers stress?—into uncharted terrain, such as how different forms of meditation alter brain circuits in an enduring way.

In large part, that research is making headway because it's much more rigorous than in the early days. Then, few studies accounted for the annoying little fact that meditators' low levels of stress might reflect self-selection (maybe only mellow people chose to meditate and stuck with it) rather than the practice itself. Nor did they consider that the reduction in stress, blood pressure, heart rate and other measures between the beginning and the end of a meditation course might reflect the placebo effect: you expect something good to happen, and it does. "You can't really control for that," says Robert Schneider of Marahishi University of Management in Iowa, a center of research on TM, "but new studies come close." Although relaxation techniques and TM both lower blood pressure, for instance, the effect of TM is twice as big. Top hospitals from Stanford to Duke are convinced: they have instituted meditation programs for patients suffering chronic pain and other ailments.

Afraid to sully their reputations, it took three decades for scientists to ask the obvious: does meditation change the brain? But in the 1990s British psychiatrist John Teasdale became intrigued with mindfulness meditation, a Buddhist practice in which you sit quietly and observe whatever thoughts and perceptions arise in your consciousness, but without judging them. He and colleagues showed that mindfulness training halves the rate at which people treated for depression relapse. That set the stage of studies showing that mere thought can alter brain activity in a long-lasting way that benefits other forms of mental illness.

Neuropsychologist Richard Davidson of the University of Wisconsin had practiced meditation since the 1970s but didn't dare study it. Only in the 1990s did he "come out of the closet," he says. Now Buddhist monks and yogis trek to his lab to have their brains scanned. They look different from the brains of undergraduates (but then, whose doesn't?), having stronger electrical waves of the kind that knit together disparate thoughts into the grand enterprise of consciousness.

Even in novices, meditation leaves its mark. An eight-week course in compassion meditation, in which volunteers focus on the wish that all beings be free from suffering, shifted brain activity from the right prefrontal cortex to the left, a pattern associated with a greater sense of well-being. And three months of intensive training (10 to 12 hours a day) in mindfulness meditation had a remarkable effect on attention. Usually, when something attracts your attention—in this study, a number interrupting a stream of letters on a screen—it takes the brain's attention machinery time to reset. If two numbers flash less than 0.5 seconds apart, most people don't see the second one. But after mindfulness meditation, with its focus on sharpening attention, volunteers detected many more numbers, Davidson's team reported this year. What happened was that the meditators used fewer attention circuits to perceive the first number and therefore had enough left over to detect the second. Meditation is still not "the answer to all your problems," but it's having a good run unveiling the brain's secrets.

© 2007