Blending pop psychology with cognitive science, Christopher Chabris and Daniel Simons write about perceptual biases and inattentional blindness in The Invisible Gorilla. Sparked by a now-famous experiment the authors performed, The Invisible Gorilla: How Our Intuitions Deceive Us is not as much about intuition as the subtitle of the book suggests. Rather, the book describes six ways our brains are fooled by illusions. Recognizing and understanding the illusions can prevent people from making critical mistakes in judgment. Those mistakes can sometimes be egregious, as when cops presume a black man is a criminal or when drivers overestimate their ability to multitask on the road. Salesmen and stage magicians count on the brain’s susceptibility to illusion to be successful. Memories of past events are reconstructions, rather than accurate recordings of the facts. Therefore, the main reason why Chabris and Simons translated their research findings into a popular book written for a general audience is to encourage all people to be more aware of their biases and work harder to overcome them.The title of The Invisible Gorilla comes from the landmark experiment in which the authors ask subjects to concentrate on counting the number of basketball passes by one team. The act of concentrating deviates attention away from the entire visual field, so that when a man in a gorilla suit walks through the scene, about half the participants fail to notice. Chabris and Simons call the phenomenon inattentional blindness because the individual is perceptually blind to the gorilla because of not paying full attention. The original experiment, which was published in 1999 in the peer-reviewed journal Perception, won awards and has made significant impact in fields like law enforcement. Lack of attention or awareness is a major problem, leading to real consequences including, as the authors show, actual fatalities. The six examples used in The Invisible Gorilla illustrate the different ways inattentional blindness and related cognitive and perceptual biases can cause major problems. The authors imply that the evidence behind The Invisible Gorilla can be used to inform public policy.

The Invisible Gorilla is divided into six chapters, plus an introduction and conclusion. Each of the six main chapters is devoted to a discussion of a type of cognitive-perceptual illusion with real world consequences. The authors open the book with a chapter called, “I Think I Would...

Using the real life example of the assault on Michael Cox in Boston, the authors show how many people develop a false sense of confidence in their own perceptual skills. This was especially true for Conley, who was convicted of the assault on Michael Cox. The authors hypothesized that Conley missed the assault on fellow officer Michael Cox for the same reasons research participants miss the gorilla. The gorilla experiment was never introduced in court to help in Conley’s appeal, but the authors suggest that cognitive science research on inattentional blindness can and should be incorporated in similar cases to help show juries how all people make mistakes not because they are incompetent but simply because of the way the brain works. Furthermore, knowing that inattentional blindness happens, law enforcement training programs could be improved to help minimize the problem.
Chabris and Simons bridge the results of the gorilla experiment with their concept of intuition. Perhaps the weakest part of The Invisible Gorilla is the way the authors assume that intuition is what caused prosecutors, jurors, and investigators to presume Conley’s guilt. In fact, it was not intuition but the facts of the case: Conley was present; Conley was the officer in charge. Therefore, Conley should have noticed that one of his own men was being assaulted. Intuition or gut instinct is not what caused either the assault on Cox or the conviction of Conley. Essentially, Chabris and Simons mistake intuition for imperfect judgment. In spite of this weakness, The Invisible Gorilla conveys sound evidence on the causes and effects of perceptual and cognitive illusions and biases. The authors also show how anecdotal evidence is problematic not just because it is anecdotal and not based on documentary fact, but also because the receiver places undue importance on the relevance and power of anecdote. Learning how to distinguish fact from fiction, and how to be a more critical thinker, is the core lesson in the Invisible Gorilla.

Several of the examples used in The Invisible Gorilla are less sensational than the opening chapter. The second, third, and fourth sections are about a basketball coach, chess players, petty criminals, weather forecasting, and hedge fund management. What all of these have in common is their reliance on patterns and forecasting. They…