Original URL: http://www.theregister.co.uk/2010/07/12/son_of_the_invisible_gorilla/

Famous 'Invisible Gorilla' trick vid gets sequel

Unexpected results of expecting unexpectedness

By Lewis Page

Posted in Science, 12th July 2010 09:27 GMT

The trick-cyclist who created a famous video in which viewers routinely fail to notice the appearance of a man in a gorilla suit among a group of people passing basketballs has produced a sequel.

In the new basketball-tossing vid, a gorilla also makes a brief appearance, but some other mildly noteworthy events also occur. Many people nowadays know that a gorilla will appear; but even though they are expecting unexpected events, those in the know are no better at clocking the non-gorilla oddities.

Unexpectedly, expecting the unexpected doesn't help one spot it.

The original gorilla vid was produced in the late 1990s by trick-cyclists Christopher Chabris and Daniel Simons. Now Simons has gone on to produce the enhanced sequel above.

"You can make two competing predictions," says Simons. "Knowing about the invisible gorilla might increase your chances of noticing other unexpected events because you know that the task tests whether people spot unexpected events. You might look for other events because you know that the experimenter is up to something."

Alternatively, "knowing about the gorilla might lead viewers to look for gorillas exclusively, and when they find one, they might fail to notice anything else out of the ordinary".

During tests with the new vid, among those who didn't know about the gorilla, about half failed to notice its appearance - just as with the old vid.

However, only 17 per cent of those who were familiar with the original gorilla video noticed one or both of the other unexpected events. Some 29 per cent of those who were unfamiliar with the original gorilla video spotted one of the other events.

"The main finding is that knowing that unexpected events might occur doesn't prevent you from missing unexpected events," Simons said.

Simons' new study based on the vid, titled Monkeying Around With the Gorillas in Our Midst, is published in new open-access journal i-Perception. ®