The researchers first asked the men to look at a series of images, all of which were obscured with the kind of static-y visual "noise" you might see on a television with a bad cable connection. Two images showed male faces, one easy to discern and the other camouflaged. Two others showed letters, again with one easy to see and one difficult to spot. The final image was pure black-and-white, splotchy noise.
The face and letter experiments were done separately, a week apart for each participant, but the set-up was the same. The men were asked to push one handheld button if they saw a face (or letter) and another if they could not.
After this initial test, the men saw another series of images and were told half contained faces (or letters). This time, however, all of the images were secretly just visual noise. The men were again asked to press a button to indicate whether they saw a face or letter in the pattern.
Your mind on pareidolia The results revealed that priming people to look for identifiable objects in random patterns is bound to create a few hits. The participants reported seeing faces 34 percent of the time and letters 38 percent of the time, despite there being none in the images they saw.