Review by Bruce Bower
People wearing gorilla suits don’t always stand out in a crowd. When volunteers were asked to count the number of ball passes made by a basketball team in a video, half never noticed a gorilla-suited intruder walking across the court doing chest thumps.
That experiment, conducted by psychologists Chabris and Simons in 1999, launches their book about the dangers of trusting one’s intuitive assumptions, unsullied by rational deliberations, of how the mind works. Invisible gorillas are an example of what the authors call “the illusion of attention,” in which people miss objects because their attention is focused tightly elsewhere.
Other mental illusions get similarly assessed. Studies show that personal memories, such as how and wh