Think your radiologist gets it right? The invisible gorilla strikes again.

A well known video shows the famous experiment of missing a gorilla walking through a basketball game when you have been instructed to count the number of times the ball is being passed during playing. (I can not refer you to a free viewing of this video, since the academic who originated it, Dan Simons, has copyrighted it, and aggressively pursues those who might wish to watch it without paying him for a DVD that contain it.) Anyway, an extension of his basic experiment gives you reason to feel even less confident about the expertise of high priced radiologists examining your X-rays. This from Drew et al.:

Researchers have shown that people often miss the occurrence of an unexpected yet salient event if they are engaged in a different task, a phenomenon known as inattentional blindness. However, demonstrations of inattentional blindness have typically involved naive observers engaged in an unfamiliar task. What about expert searchers who have spent years honing their ability to detect small abnormalities in specific types of images? We asked 24 radiologists to perform a familiar lung-nodule detection task. A gorilla, 48 times the size of the average nodule, was inserted in the last case that was presented. Eighty-three percent of the radiologists did not see the gorilla. Eye tracking revealed that the majority of those who missed the gorilla looked directly at its location. Thus, even expert searchers, operating in their domain of expertise, are vulnerable to inattentional blindness.