The other information may be irrelevant and confusing.Collecting more information, in most cases, may reinforce our judgment but does not help make it more accurate.Gladwell explains that better judgments can be executed from simplicity and frugality of information.
It presents in popular science format research from psychology and behavioral economics on the adaptive unconscious: mental processes that work rapidly and automatically from relatively little information.
It considers both the strengths of the adaptive unconscious, for example in expert judgment, and its pitfalls, such as stereotypes.
The author describes the main subject of his book as "thin-slicing": our ability to use limited information from a very narrow period of experience to come to a conclusion.
Two particular forms of unconscious bias Gladwell discusses are Implicit Association Tests and psychological priming.
Gladwell also mentions that sometimes having too much information can interfere with the accuracy of a judgment, or a doctor's diagnosis.
In what Gladwell contends is an age of information overload, he finds that experts often make better decisions with snap judgments than they do with volumes of analysis.
This is commonly called "Analysis paralysis." The challenge is to sift through and focus on only the most critical information.
This idea suggests that spontaneous decisions are often as good as—or even better than—carefully planned and considered ones.
To reinforce his ideas, Gladwell draws from a wide range of examples from science and medicine (including malpractice suits), sales and advertising, gambling, speed dating (and predicting divorce), tennis, military war games, and the movies and popular music.
Gladwell also uses many examples of regular people's experiences with "thin-slicing," including our instinctive ability to mind-read, which is how we can get to know a person's emotions just by looking at his or her face.
Gladwell explains how an expert's ability to "thin slice" can be corrupted by their likes and dislikes, prejudices, and stereotypes (even unconscious ones).