People with military experience seem to do very well in these situations. They've been taught that they can control their destiny, which is half the battle. They also have some experience in getting out of bad situations even if just through training. They know they have to make a plan and follow it and execute it.

Most Korean parents saw themselves as coaches, while American parents tended to act more like cheerleaders.

Women in particular seem to say things like, "I'm sure I'd be the one screaming and not moving in an emergency." I don't think that's the case. People who've been through really horrible life-or-death situations say that nobody behaves the way they would have expected. But that said, there are predictors.

We gauge risk literally hundreds of times per day, usually well and often subconsciously. We start assessing risk before the disaster even happens. We are doing is right now. We decide where to live and what kind of insurance to buy, just like we process all kinds of everyday risks: we wear bike helmets, or not. We buckle our seatbelts, smoke cigarettes, and let our kids stay out until midnight. Or not.

By sort of combining the research of a lot of smart people, I came up with an equation for dread [dread=uncontrollability+unfamiliarity+imaginability+suffering+scale of destruction+unfairness]. The dread equation is a simplification, but it's a way to explain why we fear something so much when it is so unlikely. Part of it is the lack of control. That's why we're more scared of plane crashes than car crashes even though we know rationally which is more dangerous.

People help way more than we expect, way more than makes sense. But when you talk to people called heroes, they often say they did it for themselves. In one case, a hero said that the cost of not doing it is so great, the sense of shame, when he knew that he was strong enough, that the fear of not doing anything was more frightening than the fear of dying.

The one thread that was most surprising and most consistent was the lack of fear that people felt at the worst moment. They felt a lot of fear in early stages, when they're just realizing what's happening. But then things really seemed to be at their peak of terror, the fear went away. You can imagine why that's useful. At that moment your brain needs to focus all its attention on surviving, so people will feel a sense of calm as their brain tries to sort out a plan.