To make a diagnosis of lung cancer, radiologists, who must read radiographs accurately can fall victim to a psychological phenomenon known as inattentional blindness.
In the classic demonstration of this phenomenon, a psychologist instructs a subject to watch a video of children passing a basketball and to count the number of passes. At the conclusion of the video, the psychologist then asks, “Did you notice the gorilla walking across the screen?” Because the subjects are so focused on the task at hand, most do not notice the gorilla.
Radiologists were tested with images similar to the ones shown above.
Even expert radiologists are susceptible to this gradual loss of focus, and a lack of appreciation of this phenomenon may jeopardize patients. In patients with lung cancer, researchers Drew et al1presented radiologists with computed tomography (CT) scan results, and instructed the radiologists to search for lung nodules on a set of 5 cross-sectional scans. For each of the 24 radiologists tested, the last of the 5 scans contained the image of a gorilla. Of the 24 radiologists tested, 20 failed to notice the gorilla. Consequently, because it is possible for radiologists to miss important abnormalities, development of a blood test to detect lung cancer would help protect patients from observational error.