by Christopher Chabris and Daniel Simons, authors of The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us (Crown Archetype, 2010)
More than a decade ago, when we did the experiment that inspired the name of our book, we had no idea that it would become as well known as it has. For us, it was mostly a way for the students in a course we were teaching to work together on a research project on perception and awareness. We created several videos that showed two groups of three people passing basketballs around. The students showed one of these videos to subjects and asked them to count how many times the people wearing white passed the ball. While they were focusing their attention on this task, half of the subjects failed to notice a person in a gorilla suit who casually strolled into the scene, thumped her chest at the camera, and walked off the other side.
This study was inspired by earlier research by the pioneering cognitive psychologist Ulric Neisser, who showed that people failed to notice when a woman carrying an open umbrella unexpectedly walked through the scene. In his videos, though, the actors were all partially transparent, and this fact enabled people to rationalize their failure to notice the umbrella woman—she was just hard to see. We went one step further and asked whether people could miss a fully visible unexpected event. We thought the answer would be no, so the results shocked us.
The gorilla video gradually gained notoriety, eventually earning us an Ig Nobel prize in psychology (awarded for achievements that “first make you laugh, and then make you think”). We started to realize that the video was popular because it gives people a deep and tangible insight into a surprising fact about how their own minds work. Normally, we literally don’t know what we are missing, but the gorilla video shows us that we must be missing a lot. It forces viewers to confront their own cognitive limitations and their assumptions about themselves.
Just as people believe, like we did, that unexpected events will capture our attention, they also believe that vivid memories are inherently accurate and that confidence is a good indicator of knowledge and skill. People readily infer cause when they shouldn’t, perceive patterns that don’t exist, and get taken in by claims for quick ways to boost brainpower. We call these mistaken ideas about the mind “everyday illusions.” The striking aspect of these intuitive misbeliefs is that our daily experiences rarely force us to confront them. The Invisible Gorilla couples our own research, and that of others, with entertaining real-world examples and personal stories that we hope will give readers a new way of looking at their own behavior and the world around them.
One of the challenges in teaching psychology is that all people are intuitive psychologists, but we don’t realize that our commonsense beliefs about the mind, brain, and behavior are often drastically wrong. When we start an introductory course in psychology or cognition with the gorilla video, it forces our students to confront the fact that their own minds don’t work the way they think. The video instantly shows that psychological science is more than just common sense, and it sets them on a path of trusting experiments over instinct and thinking more critically about accepted beliefs. We have peppered our book with similar examples and experiments that help bring home the often faulty assumptions we make about how the mind works, how we think, remember, decide, and reason. We hope that The Invisible Gorilla will make students more receptive to having their assumptions challenged, and that it will help teachers and students to think differently, in psychology courses and beyond.
Christopher Chabris, Ph.D. and Daniel Simons, Ph.D. are cognitive psychologists who have each received accolades for their research on a wide range of topics. Their “Gorillas in Our Midst” study reveals the dark side of our ability to pay attention and has quickly become one of the best-known experiments in all of psychology; it inspired a stage play and was even discussed by characters on C.S.I. Chabris, who received his Ph.D. from Harvard, is a psychology professor at Union College in New York. Simons, who received his Ph.D. from Cornell, is a psychology professor at the University of Illinois.