The author describes the main subject of his book as “thin-slicing”: our ability to gauge what is really important from a very narrow period of experience. In other words, this is an idea that spontaneous decisions are often as good as—or even better than—carefully planned and considered ones. Gladwell draws on examples from science, advertising, sales, medicine, and popular music to reinforce his ideas. Gladwell also uses many examples of regular people’s experiences with “thin-slicing.”
The book argues that intuitive judgment is developed by experience, training, and knowledge. For example, Gladwell claims that prejudice can operate at an intuitive unconscious level, even in individuals whose conscious attitudes are not prejudiced. An example is in the halo effect, where a person having a salient positive quality is thought to be superior in other, unrelated respects. Gladwell uses the 1999 killing of Amadou Diallo, where four New York policemen shot an innocent man on his doorstep 41 times, as another example of how rapid, intuitive judgment can have disastrous effects.