Recency effects as a window to generalization: separating decisional and perceptual sequential effects in category learning.
Sequential categorization of perceptual stimuli typically shows contrast from one trial to the next. Using familiar categories of animals and faces, contrast effects were dissociated from assimilation effects. Two independent main effects were observed: contrast to the preceding stimulus, and assimilation to the previous response. It is argued that contrast and assimilation may reflect different processes in categorization.