Blindness. Invisible Gorilla Test The best-known study demonstrating inattentional blindness is the Invisible Gorilla Test, conducted by Daniel Simons of the University of Illinois at Urbana–Champaign and Christopher Chabris of Harvard University. This study, a revised version of earlier studies conducted by Ulric Neisser, Neisser and Becklen in 1975, asked subjects to watch a short video of two groups of people (wearing black and white T-shirts) passing a basketball around. The subjects are told either to count the passes made by one of the teams or to keep count of bounce passes vs. aerial passes. In different versions of the video a person walks through the scene carrying an umbrella (as discussed above) or wearing a full gorilla suit. After watching the video, the subjects are asked whether they noticed anything out of the ordinary taking place. In most groups, 50% of the subjects did not report seeing the gorilla (or the person with the umbrella). Failure to perceive the anomalies is attributed to failure to attend to it while engaged in the difficult task of counting passes of the ball. These results indicate that the relationship between what is in one's visual field and perception is based much more on attention than was previously thought. Out of 228 participants of the tests, only 194 – those who did count the passes correctly – were used for statistical purposes further. The percentage was even as low as 8% in one of the 16 tests performed. The basic Simons and Chabris study was reused on British television as a public safety advert designed to point out the potential dangers to cyclists caused by inattentional blindness in motorists. In the advert the gorilla is replaced by a moonwalking bear. A real-world experiment In 1995, Officer Kenny Conley was chasing a shooting suspect. An undercover officer was in the same vicinity and was mistakenly taken down by other officers while Conley ran by and failed to notice. A jury later convicted Officer Conley of perjury and obstruction of justice, believing he had seen the fight and lied about it to protect fellow officers, yet he stood by his word that he had, in fact, not seen it. Christopher Chabris, Adam Weinberger, Matthew Fontaine and Daniel J. Simons took it upon themselves to see if this scenario was possible. They designed an experiment in which participants were asked to run about 30 feet behind