From The New York Times:
Two years ago, when Malcolm Gladwell published his best-selling “Blink: The Power of Thinking Without Thinking,” readers throughout the world were introduced to the ideas of Gerd Gigerenzer, a German social psychologist. And now he has written his own book, “Gut Feelings: The Intelligence of the Unconscious,” which he hopes will sell as well as “Blink.” “I liked Gladwell’s book,” Dr. Gigerenzer said during a visit to New York City last month. “He’s popularized the issue, including my research.”
Q: O.K., let’s start with basics: what is a gut feeling?
A: It’s a judgment that is fast. It comes quickly into a person’s consciousness. The person doesn’t know why they have this feeling. Yet, this is strong enough to make an individual act on it. What a gut instinct is not is a calculation. You do not fully know where it comes from.
My research indicates that gut feelings are based on simple rules of thumb, what we psychologists term “heuristics.” These take advantage of certain capacities of the brain that have come down to us through time, experience and evolution. Gut instincts often rely on simple cues in the environment. In most situations, when people use their instincts, they are heeding these cues and ignoring other unnecessary information.