Optical Illusion of The Day: “Inattentional Blindness” Illusion

Posted: 15 Feb 2013 09:11 AM PST

Here’s an interesting study that was performed recently on a group of 24 qualified radiologists. Each was given a series of CT scans showing diseased lungs and was told to locate 10 abnormal nodules, or white lesions on the image below. Before I continue, let’s see if you are able to spot something abnormal in the provided CT scan?

Surprisingly, the last scan this group was shown included an image of a dancing gorilla (48 times larger than the nodules they were looking for!) A staggering 83% of these qualified practitioners missed it, despite looking at the scan four times on average. You’ve almost certainly seen the “Awareness Test” video we’ve featured before. It perfectly demonstrated the theory of change blindness — a phenomenon which means we don't see changes we’re not expecting.

Researchers also determined by eye-tracking that radiologists spent 5.8 seconds looking at the scan with the gorilla, and out of the 20 radiologists who did not see the gorilla, 12 had looked directly at it” – said one of the scientists conducting the study.

According to the study the radiologists were suffering from “inattentional blindness”, a psychological phenomenon which occurs when ones brain is focused on a task and only registers what the mind considers important, or part of the job at hand.

Once the radiologists had been told that there was a gorilla somewhere in the sequence of scans they all found it immediately. Perhaps even more worrying than their inability to spot a silverback gorilla amongst the nodules is the fact that only 55 per cent of those studied were able to correctly identify all the lung abnormalities on the various scans… And they were actually looking for them!

3d illusion arts