The "Door" Study

This video shows footage from a 1998 study by Daniel Simons and Daniel Levin in which a participant fails to notice when the person he is talking to is replaced by someone else. The study was among the first to demonstrate that the phenomenon of "change blindness" can occur outside the laboratory. This was the first of many studies by Simons, Levin, and colleagues to explore how change blindness can occur in the real world.