Dancing Gorilla

Have you ever wondered how x-rays and scans reveal the condition of your lungs or brain or some other part of your body? Evidently, those mysterious black and white images make sense to radiologists. Because they know what a normal or healthy person's scan looks like; and their eyes are trained to detect abnormalities at a glance.

This is the CT scan of a patient's lung. Look closely at  the top of the right lung. Do you see anything unusual?

Don't worry if you did not spot the dancing gorilla. In a psychological experiment, several expert radiologists were shown this scan and asked to look for indications of lung cancer. A whopping 75 per cent failed to notice the gorilla!

Does the experiment suggest that medical specialists are not good at detecting signs of potentially life-threatening conditions by looking at CT scans? Not at all. This happens because they are proficient at detecting abnormal signs. When the radiologist looks at a scan with a specific focus - in this case, to spot nodules that indicate cancer in the lung - he automatically filters out other things that might distract him. Including dancing gorillas :)

This is simply how our attention system works. Not just with radiologists, but with everyone. It is called inattentional blindness. Scientists say that there is a big difference between looking and perceiving. Read more about it Here.