Contextual effects in information integration.

Category judgments of the average lengths of sets of lines were inconsistent with context-independent models of information integration: the effects of any particular line upon the judgment of average length varied inversely with the lengths of the other lines within the same set. This interaction, obtained in five separate experiments, was similar to that previously reported for auditory intensities. The judgments reflect two kinds of contextual effects: (a) withinset effects, in which the judgment of the set varies directly with the range of values within the set, and (b) between-set effects, in which the apparent interaction between the stimuli within a set depends upon the context provided by the different sets. A simple range model provides a method for separating the two types of contextual effects. The context between sets is postulated to affect only the response scale; when the responses are rescaled to allow for the between-set context, the integrated impression is dependent upon both the mean and the range of components within the set. The term "information integration"