Gladwell’s last book which grew out of a New Yorker article read like an overlong New Yorker article. This one does now. The loose premise is that many people make decisions much more quickly than they feel that they do, and that they rely on much less information to make them. Gladwell argues that, counter to our preceptions about quick decision-making, these decisions can often be fairly sound and useful ones. He guides us through a few examples of this process in action and discusses the idea of “thin slicing” whereby smaller and smaller amounts of information are being accessed (quick glimpses of people, small snatches of sounds) and yet the decisions people make ("do I know that song?" "does this person like the other person?") are often just as valid, sometimes more valid, as if they had more time to think it over.

Gladwell discusses the upside as well as the downside of this phenomena, discussing how people’s preconceptions of things like race may effect their snap judgments in ways they aren’t even aware of. He uses as an example the Implicit Association Test which tests people’s reaction times when they have to group positive and negative words with images of white or black people. Gladwell, who is half-Jamaican himself, was suprised to note that even he had a tendency to group negative words with images of black people, not consciously, but subconsciously. This book has the interestingness and research of Gladwell’s other writing along with the length and breadth of other books describing how we know what we know.