Why do some people live and others die? Why do a few stay calm and collected under extreme pressure when others panic and unravel? How do some bounce back from adversity while others collapse and surrender?...

... In any emergency, people divide into three categories, Leach says. First, there are the survivors like the 155 people on US Airways Flight 1549, who manage to save themselves in the worst situations. Second, there are unavoidable fatalities: people who never have a chance, like so many of the 200,000 people in Southeast Asia who were swept away by the tsunami of 2004. Third, there are victims who should have lived but perished unnecessarily.

After examining countless disasters and categorizing the ways people respond to life-threatening situations, Leach came up with what might be called the theory of 10-80-10. First, around 10 percent of us will handle a crisis in a relatively calm and rational state of mind. The top 10 percent are leaders, like a few passengers on the US Airways flight who took charge and guided others off the plane.

Leach says the vast majority of us--around 80 percent--fall into the second category. In a crisis, most will "quite simply be stunned and bewildered." We'll find that our "reasoning is significantly impaired and that thinking is difficult." We'll behave in "a reflexive, almost automatic or mechanical manner." We'll sweat. We'll feel sick, lethargic, numb. Our hearts may race. And we'll experience "perceptual narrowing" or tunnel vision. We'll barely hear people around us. It's OK--it's not necessarily fatal--and it doesn't last forever. The key is to recover quickly from brain lock or analysis paralysis, shake off the shock and figure out what to do.

The last group--the final 10 percent--is the one you definitely want to avoid in an emergency. Simply put, the third band does the wrong thing. They behave inappropriately and often counterproductively. In plain terms, they freak out and can't pull themselves together...