Abstract

One of the best gimmicks on the cognitive science conference circuit is the demonstration of inattentional blindness. Many readers of this journal must have already been exposed to it. For the rest we will briefly describe a striking and popular demonstration. It typically evolves during a conference talk, where the presenter provides the audience with a stimulus in the form of a small video clip of six people, three in white, three in black, who pass two basket balls around. The instruction is to count the number of passes made by the players in white. When the movie is over, the presenter asks for a response, someone provides it, and he then goes on to elicit a report: 'Did anyone notice something strange during the film?' Usually, only those who have seen the film before have, but they are not allowed to answer. The film is then replayed, but this time, the audience is instructed to look out for anything unusual. Muted, surprised laughter goes through the auditorium when someone dressed as a gorilla enters into the scene of kids playing, confronts the spectators, bangs his chest, and slowly walks out again. It seems incredible that it went unnoticed the first time around, and yet those who have been exposed to the experiment before can testify that the gorilla was indeed there in both showings of the film