NPR had a fascinating piece last month I just now ran across that (superficially) discusses a study at Harvard Medical School (HMS) that used radiologists as test subjects to look at “inattentional blindness”. This is when objects that should be easily identified visually remain invisible to people if their attention is focused elsewhere.
For example, there is an axial CT image of the chest at the top of the post. Look very closely for any nodules in the lung fields that are suspicious for malignancy.
What did you see? If you saw a suspicious nodule in the posterior right lung field, you and I saw the same thing. Of course, as a pathologist, I am hardly an authority on reading CTs, so it is possible that nodule is not even suspicious.
If you saw a gorilla in the anterior left lung field, you did better than 83% of the Harvard radiologists who were also asked to find cancerous nodules in this image.
The study, performed by Drs. Trafton Drew, a research fellow at HMS, and Jeremy Wolfe, head of the Visual Attention Lab at HMS, drew on the Invisible Gorilla Study, which is apparently one of the most famous attention studies of all time.
In the Invisible Gorilla study, people were shown a video and asked to count how many times people wearing white pass a basketball between themselves. After the short video was over, they were asked how many passes were made. What 50% of the participants failed to notice, however, was the man in a gorilla suit who casually strolled across the screen, stopped briefly in the middle of the group of people passing basketballs back and forth, thumped his chest, and then casually strolled off screen.
I find these studies to be very interesting, especially since I am in a field that is so centered around visual attentiveness.
My attendings in residency used to tell me, “The eyes do not see what the brain does not know.” In other words, if you don’t know a particular disease or diagnosis exists, you’ll never see it on a slide, because you don’t know what to look for. So read. A lot.
What they didn’t tell me is the eyes may not see what the brain isn’t looking for.
So now the medicolegal slant.
If 83% of Harvard radiologists cannot see a gorilla on a CT scan and 50% of the general population cannot see a man in a gorilla suit walk literally right in front of their face, is it malpractice or simply human nature for a physician to miss a seemingly obvious visual finding?
Is it malpractice if a radiologist looks at a PE protocol CT scan of the chest and does not notice the subpleural nodule of lung cancer that ends up killing the patient?
Is it malpractice if a pathologist does not see primary vasculitis in a lung biopsy where the clinician is asking to rule out malignancy and the patient dies of massive pulmonary hemorrhage?
Is it malpractice if a surgeon does not see a malignancy on the anterior surface of the liver during a laparotomy for a bowel resection and the patient has to have a second surgery?
I would venture to say most people (including all plaintiff attorneys) would say yes to all three scenarios. But like so many things in life, the answer may not be black and white. Perhaps physicians are wrongly held to an unrealistic standard that ignores our humanity.
Postscript-If anyone is successful during a malpractice trial utilizing the Invisible Gorilla defense, please let me know. I’ll write it up.