Change blindness studies show that if we are paying very close attention to one thing, we often fail to notice other things in our field of vision—even very obvious things.
As an example, scientists recruited 24 experienced and credentialed radiologists-and a comparable group of naïve volunteers. They tracked their eye movements as they examined five patients’ CT scans, each made up of hundreds of images of lung tissue. Each case had about 10 nodules (minuscule signs of lung cancer) hiding somewhere in the scans, and the radiologists were instructed to click on these nodules with a mouse. On the final case, the scientists inserted a tiny image of a gorilla into the lung. They wanted to see if the radiologists, focused on the telltale nodules, would be blind to the easily detectable and highly irregular gorilla… The gorilla was minuscule, but huge compared to the nodules. It was about the size of a box of matches-or 48 times the size of a typical nodule.
After they were done scrolling through the images as much as they wanted, the scientists asked them: Did that last trial seem any different? Did you notice anything unusual on the final trial? And finally: Did you see a gorilla on the final trial? 20 of the 24 radiologists failed to see the gorilla, despite scrolling past it more than four times on average. And this was not because it was difficult to see: When shown the image again after the experiment, all of them saw the gorilla. What’s more, the eye-tracking data showed clearly that most of those who did not see the gorilla did in fact look right at it. CRAZY !!! Learn more here.