In January 1995, the Boston Police Department received a call that a police officer had been shot and that four black suspects were fleeing the scene in a car. After a lengthy chase, the suspects jumped out of the car and ran in different directions. During the confusion, a group of police mistook Michael Cox, a black undercover officer, for one of the suspects, hit him on the head from behind, and began to beat him.
While the officers were attacking Cox, Officer Kenneth Conley spotted one of the suspects from his car and pursued him on foot. In the course of the chase, he ran directly by the beating of Cox. The officers hitting Cox eventually realized their mistake and dispersed without seeking help for their victim.
Later, during an investigation into Cox's beating, no officer would admit to participating in the incident. However, Conley said he was in the area but insisted that he did not see that the attack was occurring. The investigators did not believe his story, and Conley was convicted of perjury and obstruction of justice.
Inspired by this event, reports NPR, psychologists Chris Chabris from Union College and Daniel Simons from the University of Illinois decided that they would test inattentional blindness - that is, the tendency of human beings to tune out something that is right in front of them when they are focused on something else.
In their experiment, the test subject was told to run behind a jogger and count the number of times the jogger touched his hat. During the experiment, Chabris and Simons staged a fight among some students slightly to the side of the running path. When asked about the fight afterward, a surprisingly high number of subjects reported that they had not noticed it.
This experiment raises a number of questions about the potential effect of inattentional blindness on the legal process. How reliable is testimony from a witness, for instance, when that witness was focused on something else at the time of the alleged crime?
It would also seem to add a new tool to the arsenal of defense attorneys, who could use this study and others like it to discount the credibility of the ID of the defendant, or, as in the case of Officer Conley, to argue that the defendant could not have noticed something others might expect him to notice.
To test your own level of selective attention, click on the video above and see how you do.