by Daniel Simons, as told to Discover’s Valerie Ross. Simons is a professor of psychology at the University of Illinois, where he studies attention, perception, and memory—and how much worse people are with those skills than they think. He is the co-author, with fellow psychologist Chris Chabris, of The Invisible Gorilla.
Late one January night in 1995, Boston police officer Kenny Conley ran right past the site of a brutal beating without doing a thing about it. The case received extensive media coverage because the victim was an undercover police officer and the aggressors were other cops. Conley steadfastly refused to admit having seen anything, and he was tried and convicted of perjury and obstruction of justice. Prosecutors, jurors, and judges took Conley’s denial to reflect an unwillingness to testify against other cops, a lie by omission. How could you run right past something as dramatic as a violent attack without seeing it? Chris Chabris and I used this example to open our book because it illustrates two fundamental aspects of how our minds work. First, we experience inattentional blindness, a failure to notice unexpected events that fall outside the focus of our attention. Second, we are largely oblivious to the limits of perception, attention, and awareness; we think that we are far more likely to notice unexpected events than we actually are.
Chabris and I have studied this phenomenon of inattentional blindness for many years. Our best-known study was based on earlier work by Ulric Neisser: We asked subjects to count how many times three players wearing white shirts passed a basketball while ignoring players wearing black who passed their own ball. We found that about 50 percent of subjects failed to notice when a person in a gorilla suit unexpectedly walked through the scene.
The mismatch between what we see and what we think we see has profound implications for our court system. As our research has shown, we can fail to notice something obvious if we are focused on something else. Yet, most jurors likely hold the mistaken belief that we should see anything that happens right before our eyes. Kenny Conley was convicted on the strength of that intuitive belief. Many others likely languish in jail due to similarly mistaken beliefs about the accuracy of memory. By studying these limits of attention and memory and our beliefs about them, we identify cases in which our beliefs diverge from reality. Ideally, we can then reveal these “invisible gorillas” in the court system.