Visual Sampling and Estimates of the Location of Information on Chest Films
Harold L. Kundel · Investigative Radiology · 1974
Both radiologists and laymen only fixate selected portions of chest x-ray films with the fovea. Fifty per cent of fixations are concentrated on twenty per cent of the total film area. The regions selected for foveal fixation are different for both groups of viewers but within groups there is good correlation between anatomic regions verbally selected as important and the location of fixations determined by recording eye movements. The radiologists have a fixation distribution for normal chests that is similar to an estimate of the probability distribution of abnormalities on chest films. It is hypothesized that radiologists look where the probability of finding an abnormality is highest. Even when an abnormality is found and attracts a large proportion of fixations, there is an underlying distribution similar to that used for normal films.