Talking to Strangers: What We Should Know About the People We Don’t Know

by Malcolm Gladwell

The person who searches your hand luggage at the airport, for example, is also engaged in a haystack search. And from time to time, the Transportation Security Administration (TSA) conducts audits at different airports. They slip a gun or a fake bomb into a piece of luggage. What do they find? That 95 percent of the time, the guns and bombs go undetected. This is not because airport screeners are lazy or incompetent. Rather, it is because the haystack search represents a direct challenge to the human tendency to default to truth. The airport screener sees something, and maybe it looks a little suspicious. But she looks up at the line of very ordinary-looking travelers waiting patiently, and she remembers that in two years on the job she’s never seen a real gun. She knows, in fact, that in a typical year the TSA screens 1.7 billion carry-on bags, and out of that number finds only a few thousand handguns. That’s a hit rate of .0001 percent—which means the odds are that if she kept doing her job for another 50 years she would never see a gun. So she sees the suspicious object inserted by the TSA’s auditors, and she lets it go.