What's Your Intuition?

After many more interviews with veteran firefighters, Klein developed a radically different understanding of how intuition might work. Over time, as firefighters accumulate a storehouse of experiences, they subconsciously categorize fires according to how they should react to them. They create one mental catalog for fires that call for a search and rescue and another one for fires that require an interior attack. Then they race through their memories in a hyperdrive search to find a prototypical fire that resembles the fire that they are confronting. As soon as they recognize the right match, they swing into action.

Thought of this way, intuition is really a matter of learning how to see -- of looking for cues or patterns that ultimately show you what to do. The commander who saved his crew didn't have ESP, he simply had "SP." His sensory perception detected subtle details -- small-but-stubborn fire, extreme heat, eerie quiet -- that would have been invisible to less-experienced firefighters. "Experienced decision makers see a different world than novices do," concludes Klein. "And what they see tells them what they should do. Ultimately, intuition is all about perception. The formal rules of decision making are almost incidental."

The critical role of recognition in decision making came into sharper focus when Beth Crandall, 51, vice president of research operations at Klein Associates, got a contract from the National Institutes of Health to study how intensive-care nurses make decisions. In 1989, she interviewed 19 nurses who worked in the neonatal ward of Miami Valley Hospital in Dayton, Ohio. The nurses cared for newborns in distress -- some postmature, some premature. When premature babies develop a septic condition or an infection, it can rapidly spread throughout their bodies and kill them. Detecting sepsis quickly is critical. Crandall heard dozens of stories from nurses who would glance at an infant, instantly recognize that the baby was succumbing to an infection, and take emergency action to save the baby's life. How did they know whether to act? Almost always, Crandall got the same answer: "You just know."

But once again, the more accurate answer was this: "recognition." By asking each nurse to recall specific details of when she suspected sepsis, Crandall compiled a list of visual cues showing that the baby was in the early stages of an infection: Its complexion would fade from a healthy pink to a grayish green; it would cry frequently, but then one day it would become listless and lethargic; it would feed abnormally, causing its abdomen to distend slightly. Each of these cues is extremely subtle, but taken together, they are a danger signal to an experienced nurse.

"When we reviewed the list of cues with specialists in neonatology, we found that half of the cues had never appeared in medical literature at that time," recalls Klein. "The head of the unit asked if we would train new nurses. We told her that everything on that list came from her own nurses. She said, 'It doesn't matter, we can't articulate what we see anymore -- or how we see it.' So Beth developed and tested a series of training materials to help the nurses."

Gut Choice, Best Choice

Still, Klein was troubled by another mystery. Once nurses and firefighters make a decision, how do they know whether their course of action is any good?

He thought he knew the answer after reading a study by Peer Soelberg, who taught a course on decision making at MIT's Sloan School of Management during the late 1960s. Soelberg advocated a classic decision-making strategy: Identify options, evaluate them, rate them, and then pick the option with the highest rating. For his PhD dissertation, Soelberg decided to test whether his students would use this strategy to determine which job offer they should accept. To his great surprise, Soelberg discovered that his students rejected the very strategy that he had taught. Instead, they made a gut choice. Then they compared other job offers with their favorite, to justify that their favorite was indeed the better offer.

Klein believed that fire commanders use the same tactic. Instead of weighing lots of options, he theorized that they make an instinctive decision -- say, to attack a burning house from the rear -- and then compare it with alternatives. "I thought I'd come up with a daring theory," says Klein. "But the fire commanders insisted that they never considered options of any kind. As it turned out, my theory was way too conservative."

Klein took a harder look at the commanders' stories and began to understand why they don't have to compare options. Once they make a decision, they evaluate it by rapidly running a mental simulation. They imagine how a course of action may unfold and how it may ultimately play out. The process is akin to building a sequence of snapshots, says Klein, and then observing what occurs.

"If everything works out okay, the commanders stick with their choice. But if they discover unintended consequences that could get them into trouble, they discard that solution and look for another one. They might run through several choices, but they never compare one option with another. They rapidly evaluate each choice on its own merits, even if they cycle through several possibilities. They don't need the best solution. They just need the one that works."