Gorillas in our midst: sustained inattentional blindness for dynamic events.
There were 228 participants, recruited via volunteer sampling. They were offered a rewards of a candy bar or a smal, payment.
Researchers created four video tapes showing teams of three players moving randomly around the space passing an orange ball.
Twenty one experimenters tested participants individually, using a standardised instruction script and written protocol.
Participants were shown the clip on television ranging from 13-36 inches. In one condition a woman with an open umbrella walked in and in the other condition P's saw a gorilla.
There were two styles of video; transparent and opaque and the third variable was the team colour P's were asked to follow; black or white. P's were asked to keep a silent mental count of total passes or count each bounce pass and aerial pass separately (hard condition.)
P's were then asked a series of question about an 'unusual event' and of the 192 participants (the useful data) 46% failed to notice the event.