Structures in two-choice reaction-time data.

This study served (a) to illustrate a maximum likelihood estimation procedure for metric multidimensional scaling applied to speeded same–different judgments, (b) to compare the spatial representations of various stimulus sets derived from dissimilarity data obtained in conditions of data- and resource-limitations with the spatial representations of the same stimulus sets derived from dissimilarity measures collected in conditions of unlimited viewing and/or responding, and (c) to examine the concepts of integrality and separability as they apply to the dimensional decomposability of stimuli. The results showed that although the same spatial metrics best represented perceived dissimilarities for each subject within each stimulus set, individual differences and divergence with results obtained on similar stimulus sets in different conditions were apparent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)