The great psychologist William James was Gertrude Stein's teacher and mentor. As legend tells it, James once posed a single question on a final examination: "What is risk?" Stein wrote, "This is," walked out of the examination room, and went about her business. Supposedly James gave Stein an A.
After a tragedy such as the one last week in Boston, people have a heightened sense of risk. If a flood, an earthquake, a violent crime or a terrorist attack has occurred in the recent past, people tend to have a feeling of vulnerability, captured in the alarming idea that "you can't be safe anywhere." Often that feeling is far greater than reality warrants. This is so because of two facts about how human beings respond to risk.
The first is that we often assess probabilities not by looking at statistics, but by asking what events come readily to mind. If you are unable to think of a case in which a crime occurred in your neighborhood, or of a situation in which an accident resulted from talking on a mobile phone while driving, you might not much worry about crime or distracted driving. But if your neighbor was recently robbed, or if a friend was badly injured in a crash caused by distracted driving, you might think that the risk is pretty high.
Social scientists emphasize that people use the "availability heuristic," which means that we assess risks by asking whether a bad (or good) event is cognitively "available." It is hardly unreasonable to use the availability heuristic, yet we can be misled by it, and far more frightened than we need to be.
A bad event may have occurred in the recent past, but it might have been a fluke, and the risk might be really low. Even if there was a robbery in your neighborhood last month, there might be no reason for alarm.