Friday, January 25, 2013

Psychology and the invisible gorilla

David Denofreo photo
If a gorilla walked into the room, you'd notice, right? No matter what you were doing? No matter how busy you were? But research shows that about half of us would not notice the gorilla. Don't believe it? Read on to learn more about one of psychology's more famous experiments.

By Graham Rodwell, Chair, Psychology Department


The Invisible Gorilla has become one of the most well-known experiments in modern psychology. First conducted by Chris Chabris and Dan Simons at Harvard in 1998, the experiment was originally designed to show that when we pay really close attention to something we are often blind to other events.

In this research Chabris and Simons made a short film of two teams of people (a white team and a black team) moving around and passing basketballs. Halfway through the video a female student wearing a gorilla suit walks through the scene for nine seconds, including a period when she stops, faces the camera and thumps her chest. The participants who watched the film were told to count and report the passes made by the white team and to ignore the passes made by the black team. At the end they were asked whether they had noticed anything unusual. Roughly half of them did not notice the gorilla.

One of the most important findings of this and subsequent research was that almost all participants shared the false belief that everyone would normally notice an event as unexpected and striking as a gorilla. Participants who did see it found it hard to believe that other participants had missed it. Participants who hadn’t seen it found it very hard to accept that they had missed it until shown the evidence, and even then they often expressed surprise and disbelief.