On the relation between decision rules and perceptual representation in multidimensional perceptual categorization

This article examines the relation between changing categorization decision rules and the nature of the underlying perceptual representation. Observer s completed a matching task that required them to adjust the length and ori entation of a single line stimulus until they perceived it to "match" a sec ond line stimulus (Alfonso-Reese, 1996, 1997). The same observers then comp leted four categorization tasks with the same stimuli. Data from the matchi ng task were used to estimate a perceptual representation for each stimulus and observer. Three hypotheses regarding potential interactions between ca tegorization decision rules and perceptual representation were examined. On e assumed that there was no interaction between decision rules and perceptu al representation. The second assumed that linear categorization rules affe ct the perceptual representation differently from nonlinear categorization rules. The third assumed that dimensional integration rules affected the pe rceptual representation differently from decision rules that require the ob server to set a criterion along one stimulus dimension while ignoring the o ther; this is referred to as decisional selective attention. The results su ggested that (1) the matching task perceptual representation provided a goo d account of the categorization data, (2) decisional selective attention af fected the perceptual representation differently from decisional integratio n, and (3) decisional selective attention generally decreased the perceptua l variability along the attended dimension.