Abstract

A cluster of experiments on “Change Blindness”, “Inattentional Blindness” and associated phenomena appear to demonstrate extremely counter intuitive results. According to one plausible characterisation, these results show that we consciously take in far less of the visual world than it seems we are aware of. It is worth briefly summarising the results of two recent sets of experiments, in order to give a flavour of this work. In ‘Gorillas in our Midst’ (Simons, D. and Chabris, C., Perception, 1999, 28), subjects were asked to perform a task that involved watching a video of a casual basketball game that lasts for about a minute. The task involves counting the number of consecutive passes between members of the one of the teams. While the basketball is being thrown from player to player, something unexpected takes place: a person dressed in a black gorilla-suit walks through the play, stops briefly in the centre of the picture, thumps his chest, and then walks off. Although most subjects correctly record the number of passes made by the team, at least half of these subjects fail to notice the gorilla-suited interloper, who is visible for about nine seconds. When shown the video sequence a second time they are amazed to observe what they had previously overlooked