GL1800Riders Forums banner
1 - 6 of 6 Posts

4,027 Posts
Discussion Starter · #1 ·
None So Blind

Perceptual-blindness experiments challenge the validity of eyewitness testimony and the metaphor of memory as a video recording.

Picture yourself watching a one-minute video of two teams of three players each. One team wears white shirts and the other black shirts, and the members move around one another in a small room tossing two basketballs. Your task is to count the number of passes made by the white team—not easy given the weaving movement of the players. Unexpectedly, after 35 seconds a gorilla enters the room, walks directly through the farrago of bodies, thumps his chest and, nine seconds later, exits. Would you see the gorilla?

Most of us believe we would. In fact, 50 percent of subjects in this remarkable experiment by Daniel J. Simons of the University of Illinois and Christopher F. Chabris of Harvard University did not see the gorilla, even when asked if they noticed anything unusual (see their paper "Gorillas in Our Midst"). The effect is called inattentional blindness. When attending to one task— say, talking on a cell phone while driving— many of us become blind to dynamic events, such as a gorilla in the crosswalk.

I've incorporated the gorilla video into my lecture on science and skepticism given at universities around the country. I always ask for a show of hands of those who did not see the gorilla during the first viewing. About half of the more than 10,000 students I encountered last year confessed their perceptual blindness. Many were stunned, accusing me of showing two different clips. Simons had the same experience: "We actually rewound the videotape to make sure subjects knew we were showing them the same clip."

These experiments reveal our perceptual vainglory, as well as a fundamental misunderstanding of how the brain works. We think of our eyes as video cameras and our brains as blank tapes to be filled with sensory inputs. Memory, in this model, is simply rewinding the tape and playing it back in the theater of the mind, in which some cortical commander watches the show and reports to a higher homunculus what it saw.

This is not the case. The perceptual system and the brain that analyzes its data are far more complex. As a consequence, much of what passes before our eyes may be invisible to a brain that is focused on something else. "The mistaken belief that important events will automatically draw attention is exactly why these findings are surprising; it is also what gives them some practical implications," Simons told me. "By taking for granted that unexpected events will be seen, people often are not as vigilant as they could be in actively anticipating such events."

Driving is an example. "Many accident reports include claims like, 'I looked right there and never saw them,' " Simons notes. "Motorcyclists and bicyclists are often the victims in such cases. One explanation is that car drivers expect other cars but not bikes, so even if they look right at the bike, they sometimes might not see it." Simons recounts a study by NASA research scientist Richard F. Haines of pilots who were attempting to land a plane in a simulator with the critical flight information superimposed on the windshield. "Under these conditions, some pilots failed to notice that a plane on the ground was blocking their path."

(rest of article intentionally omitted -- go buy the magazine...).

Michael Shermer is publisher of Skeptic ( and author of The Science of Good and Evil.

Similar science is used in the advertising industry. I recently (just before the super bowl) read an article about Madison Avenue ad agencies and their never ending endeavour to get their clients' messages across to us. It talked about how test groups of people viewing the same commercial would actually see different things (much like your gorilla). We all know about jingles but this was all new stuff to me. I was stunned at how much science goes into the making of a commercial. But, I guess if you're spending $2m for a 30 second ad you can't afford to not get your message across.
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.