The program reenacts a study conducted by Daniel Simons and Christopher Chabris of Harvard University. A group of observers watch a videotape of three yellow-shirted players tossing a basketball. Three blue-shirted basketball players are also on the court. Observers are instructed to count the number of times the yellow-shirted men toss the ball. Midway through the tape a gorilla-suited confederate walks across the court, at one point stopping to thump its chest. At the conclusion of the tape, the observers are asked for their count of the tosses as well as whether anyone saw something unusual. When the videotape is replayed without the request to count tosses, observers express genuine disbelief that they could have missed the gorilla.