Julianne Greenberg is a radiologist who hunts for breast cancer. Hundreds of times each day, she visually searches digitized black-and-white X-rays filled with images of breast tissue.
Greenberg's work is very much like the work of another class of professionals whose failures have recently dominated news headlines: airport baggage screeners. Like Greenberg, they must hunt through hundreds if not thousands of confusing visual images in search of targets that are extremely rare and frequently hard to distinguish.
A recent study of the problems involved in visually searching for exceedingly rare targets comes to an unsettling conclusion: "If you don't find it often, you often don't find it," says author Jeremy Wolfe. In other words, we are not very good at finding things that are rarely there.
Full story from NPR