Portal de Periódicos da CAPES

Contextual effects in information integration.

1971; American Psychological Association; Volume: 88; Issue: 2 Linguagem: Inglês

10.1037/h0030880

1946-1941

Michael H. Birnbaum, Allen Parducci, Robert K. Gifford,

Visual and Cognitive Learning Processes

Category judgments of the average lengths of sets of lines were inconsistent with context-independent of 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 refers to the process whereby the psychological values of several stimuli are combined to produce a single impression. For example, 5s have been asked to judge the overall loudness of four bursts of noise of varied intensity (Parducci, Thaler, & Anderson, 1968). Additive of integration assume that the integrated impression is simply a weighted sum (or average) of the values associated with each of the component stimuli comprising the set. In the usual application of such models, the effect of each component stimulus is assumed to be independent of the other stimuli. The term models will be used here to represent this assumption of independence from context. In apparent contradiction to additive models, the loudness study demonstrated that the effect of the intensity at any one serial position within the set was greater when the intensities in the other three serial positions were lower. This finding was also