"Intuition is hot," social psychologist and researcher David Myers says. "There is an explosion of research on how unconscious, automatic, out-of-sight thinking guides our lives." There are courses on "intuitive learning, healing, investing, selling and managing." Intuition, he says, is "an effortless, immediate, unreasoned (not thought about) sense of truth." It is a good thing: It feeds creativity, expertise and spirituality, he says.

"Scientists, writers and artists have all marveled at the outcroppings of their unconscious, intuitive minds. In times of relaxation, creative insights and impulses often appear like Web site pop-up ads."

Everyone makes use of information that seems to bubble up from the subconscious, from presidents on down, he says. Intuition shapes what we fear, our impressions of people, what politicians do in times of crisis, what hunches gamblers play, what decisions are made by those hiring applicants for jobs.

But there is a definite downside to going with one's gut, Myers says in Intuition: Its Powers and Perils. "Smart thinkers will also want to check their intuitions against available evidence. Our gut intuitions are terrific at some things, such as instantly reading emotions in others' faces, but not so good at others, such as guessing about the stock market, assessing risks and predicting football outcomes."

Myers, a psychology professor at Hope College in Holland, Mich., says intuition could be a poor servant for many reasons.

A hunch might be the result of overconfidence in our own abilities or knowledge, a faulty or reconstructed memory of the past, hindsight that convinces us we "knew it all along" when we did not, misjudging the intensity of our emotions or reactions to events, or mispredicting our own behavior.

Myers marshals the latest research to document when everyday intuition can be wrong, ranging from judgments made in courtrooms to hunches played in the stock market.

One of the most enduring intuitive myths he uses research to debunk is that of the "hot hand" in basketball. Coaches often believe that because a player has sunk several baskets, he will make the next one. Statistically that is simply not true, he says.

Intuition has the endorsement of many heavyweights. Pioneering psychologist Carl Jung called it one of the four ways people function, along with feeling, thinking and sensing. Psychologist Marcia Emery, author of three books on intuition, calls it "the deepest wisdom of the human soul."

But many urge caution. "Intuition makes people feel more powerful, more effective," says Stuart Vyse, a psychologist at Connecticut College in New London, Conn. "But it has been shown over and over again that gut reactions are not accurate. It is a mistake to base a decision on a gut feeling."

Myers says he and other researchers are not trying to destroy intuition. He applauds its "unbidden insights and inspirations." He aims instead, he says "to fortify our intuition, to sharpen our thinking and to deepen our wisdom."