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How to See Red

Psychologists Daniel Simons and Christopher Chabris conducted a simple test. In a 1999 experiment, they asked subjects to watch a video of two teams playing basketball. One team wore white shirts while the other team wore black shirts. The directive was simple: count the number of passes between the team members in white shirts.

The test subjects were not warned that, in the middle of the game, a woman dressed in a gorilla suit would walk into the video, thump her chest, and walk out. The results were shocking. The test subjects either saw the gorilla or correctly counted the number of passes. Never both. 

The now-famous experiment demonstrates how faulty human perception can be by revealing a wonky bit of brain processing called “fixation error.” When asked to concentrate on a given task, people block out other stimuli to complete that task.

In 2011, the researchers published a book, The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us, on the experiment as well as several follow-up studies that replicated the findings. In one of these experiments, The Door Study, test subjects were asked to give directions to a passerby on the street—who was one of the researchers. During the conversation, other researchers, carrying a door, walked between the person giving the instruction and the one receiving them. As the door obstructed the test subject’s vision, the person asking for directions was secretly replaced with one of the door carriers. Fewer than half of the participants noticed that they were talking to a different person.

Subsequent research has reinforced this phenomenon in the workplace. In a 2013 study conducted by researchers from Harvard Medical School and Brigham Young University, 20 of 24 radiologists did not see a gorilla embedded in the image​ of a CT scan. However, the radiologists did better than the untrained test subjects. They missed the gorilla 100 percent of the time. (Links to all of these experiments are available in the online version of this article.)

Fixation error exposes gaps in our visual sphere. When we are focused on a task, we don’t process events that are happening right in front of us. Noticing and understanding human behavior in the workplace is much more complex, incorporating visual cues as well as more subtle indicators such as language, posture, and attitude. Experts continue to grapple with the problem of identifying behavioral cues that might indicate that a peer or coworker could be dangerous.

To help security managers and nonsecurity employees see the red flags that precede workplace violence, this month’s cover story by Assistant Editor Megan Gates explores the case of Vester Lee Flanagan II, who shot and killed two of his coworkers on live television last summer. Through Flanagan’s numerous lawsuits, experts have unprecedented access to his state of mind. Flanagan’s actions could be instructive in helping security managers avoid fixation errors and see the gorilla in the room before it’s too late.