It was a summer evening when Tony Cornell tried to make the residents of Cambridge, England see a ghost. He got dressed up in a sheet and walked through a public park waving his arms about. Meanwhile his assistants observed the bystanders for any hint that they noticed something strange. No, this wasn’t Candid Camera. Cornell was a researcher interested in the paranormal. The idea was first to get people to notice the spectacle, and then see how they understood what their eyes were telling them. Would they see the apparition as a genuine ghost or as something more mundane, like a bloke in a bed sheet?
The plan was foiled when not a single bystander so much as raised an eye brow. Several cows did notice, however, and they followed Cornell on his ghostly rambles. Was it just a fluke, or did people “not want to see” the besheeted man, as Cornell concluded in his 1959 report?
Okay, that stunt was not a very good experiment, but twenty years later the eminent psychologist Ulric Neisser did a better job. He filmed a video of two teams of students passing a basketball back and forth, and superimposed another video of a girl with an umbrella walking right through the center of the screen. When he asked subjects in his study to count the number of times the ball was passed, an astonishing 79 percent failed to notice the girl with the umbrella. In the years since, hundreds of studies have backed up the idea that when attention is occupied with one thing, people often fail to notice other things right before their eyes.