Blink: The Power of Thinking Without Thinking by Canadian journalist and public speaker Malcolm Gladwell provides a compelling analysis (drawn from scientific studies as well as case histories) of how our “gut-reactions” or “snap judgments” take place, what their consequences (positive or negative) might be, and how our awareness of unconscious thoughts at work can help us to identify, evaluate, and manage our reactions wisely.

Gladwell does not make the claim that gut feelings or snap judgments are clearly right or wrong in every case. In his “Introduction: The Statue that Didn’t Look Right,” he recounts the case of the J. Paul Getty Museum’s purchase of a purportedly ancient Greek statue. After fourteen months of deliberation and research, the museum’s experts decided that the statue was authentic and went ahead with the very costly purchase. However, quite a few art experts later expressed “a feeling” that something was wrong and that the statue may have been a brilliant forgery. In the end, the museum decided to display the statue with a placard that reads “about 350 B.C. or modern forgery.” This true story exemplifies the idea that instinctive decisions can be just as valuable as decisions that are drawn out and pondered over time.

Gladwell introduces the concept of “thin-slicing,” the quick process by which people size up an individual and come to sweeping conclusions, based on limited past experience and using only bits and pieces of superficial information—for example, having a quick look at a dorm room to assess the occupant’s personality. Despite the speed with which they are made, sometimes these quick conclusions are accurate.

The author also discusses how subtle nonverbal messages that provide quick cues have been studied and classified. For example, the Facial Coding Action System (FACS) categorizes all the muscles in the face used in expressing emotion to interprets facial expressions (including insincere smiles). Gladwell points out that some people with autism may not be able to interpret nonverbal cues, which contribute a great deal to our “gut” assessments of what goes on beneath the surface of spoken words.

Depending on the situation, the quick judgements made using thin-slicing can be an impediment. Gladwell provides the example of Bob Golomb, a car dealer in New Jersey, who makes a conscious decision to side-step the thin-slicing process when working with customers. By not putting them into mental categories based on ethnicity or gender, he is able to focus entirely on making the sale and is far more successful than his peers.

Gladwell makes it clear that acting on conclusions drawn from a small sample of information can sometimes lead to incorrect assessments and unintended consequences, as in the 1980s Pepsi Challenge Campaign. In this experiment, a majority of people expressed a preference for a sip of Pepsi rather than Coke, causing Coke to formulate the "New Coke," which tasted sweeter and more like Pepsi. Much to the surprise of the Coca-Cola Corporation, sales went down and their new product failed miserably. Gladwell cites this as an example of thin-slicing misuse. What was evaluated was only a consumer's reaction to a single sip, and it turned out that this initial reaction had little correlation with an individual's willingness to consume a whole bottle. This same error can happen when we judge a person or situation based on a thin-slice of information.

Thin-slicing can have much more serious consequences, as in the 1999 case of the four officers who made the split-second decision to shoot Guinean immigrant Amadou Diallou when they mistook his wallet for a gun. Better awareness and training can help people identify sudden thin-slicing reactions as they are taking place, which can perhaps help them avoid making regrettable decisions.

In his conclusion, “Listening to Your Eyes: The Lessons of Blink,” Gladwell writes that awareness of our “powers of rapid recognition,” especially within the first two seconds in which we see something, can help us make good use of this innate ability.