Sequential dependencies in categorical judgments of radiographic images

Sequential context effects, the psychological interactions occurring between the events of successive trials when a sequence of similar stimuli are judged, have interested psychologists for decades. It has been well established that individuals exhibit sequential context effects in psychophysical experiments involving unidimensional stimuli. Recent evidence shows that these effects generalize to quantitative judgments of more complex multidimensional stimuli such as images of faces, chairs, and shoes. In this article, we test for the presence of sequential context effects by re-examining previously published data on categorical judgments of 234 complex radiographic images made by 20 experienced physicians and 20 medical students engaged in an online training task. We found that medical students, but not experienced physicians, displayed evidence of sequential context effects. We also found evidence suggesting that as the students learned over blocks of trials, they tended to shift from relative comparisons between consecutive images toward more independent comparisons of each image against (strengthening) internalized standards.