The invisible gorilla

Do you know what you’re missing? You might be surprised.

A friend forwarded an e-mail to me, sometime in 2002, with the subject line, “I don’t normally forward these, but you HAVE to see this.” I clicked on the link and started watching a video of two teams passing a basketball. The scrolling text below the video told me to count the passes made by the team in the white shirts, while ignoring the passes made by the team in the black shirts. I focused intently on the white-shirted team. At the end of the video, the text asked if I’d counted 34 passes. Score one for me! I had in fact counted every pass. Then the text asked if I had seen the gorilla. I was sure it was a lame joke, certain there had been no gorilla, but I backed the video up and watched it a second time without counting passes. Sure enough, midway through the video, a person wearing a black gorilla costume walked to the middle of the court, stopped, beat his or her chest and then walked off. Total on-screen time: 9 seconds.

I was incredulous. As a dentist, I believed my attention to detail was better than average. Surely this was some video sleight of hand and not a mistake on my part. But I had fallen into the trap of Harvard psychologists Christopher Chabris and Daniel Simons, who created the video to test selective attention. Their 1999 research showed 50% of people would miss the gorilla. They found no pattern in age, gender or education level to explain who saw it and who didn’t. What they did find was people missed the gorilla specifically because they were not looking for anything out of the ordinary. Our brains are wired to expect the expected, and as dentists we are trained to do the same. As the adage goes, “If you hear hoof beats in Georgia then you should expect a horse” rather than a zebra-or, in this case, a gorilla.

Chabris and Simons dubbed the phenomenon “inattentional blindness.”  In their 2010 book, The Invisible Gorilla and Other Ways Our Intuitions Deceive Us, they build on that research, sharing some incredible examples of how our memory and attention are not completely reliable. We think we see the world as it is, but the authors tell us “our vivid visual experience belies a striking mental blindness.”  This is not a bug in our software, so to speak, but rather an inherent limitation. Because the brain is a closed system, it has finite resources. We unconsciously allocate those resources, choosing what to “see” and what to ignore.   

This blindness can affect the dental practice as well. Feeling rushed and overly busy, we walk into a hygiene check, look at the bitewings and completely miss the decay. Similarly, a dentist who is completely focused on the practice’s “bottom line” numbers may overlook the fact that the entire office is not functioning at its best and is slowly coming apart at the seams.  

Chabris and Simons cite many examples of the limitations of our brains, but they do not propose a remedy for this blind spot in our attention. While each story is interesting, the book lacks an overarching story line to tie the vignettes together.  

Nevertheless, the findings make us aware of our own limitations. We can create processes to compensate for these blind spots and reduce error. Having your hygienists review bitewings and comparing their findings with your own is a good way to reduce the chances of missing an important finding. Periodic team sessions with a practice manager may help the dentist take a more global view of the practice, thereby raising team morale and increasing overall production. Such practices take into account the holes in our attention and close them to the gorillas that we can all miss.

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The Benchmark column is written by the directors of the Atlanta Center for Dental Excellence, an alliance of practicing clinicians dedicated to progress in dentistry. The ACDE advises dental companies on product development and marketing, and provides PACE-approved high-level continuing education. To learn more, visit theacde.com, or contact Molly Thompson at info@theacde.com.

About the author

Brenton Young, DDS, is co-author of A Survival Guide to Clinical Dentistry and has lectured at the UNC School of Dentistry and internationally. His work with the ACDE focuses on the impact that EQ (Emotional Quotient) has on a dentist’s success in the dental office and in his or her personal life. Dr. Young is married with two college-age children and practices general dentistry in Shelby, North Carolina.