Simultaneous processing of typal and dimensional variation among multidimensional events

If class structure exists within a multidimensional configuration, two sources of variation among elements are potentially present: typal variation due to class membership and dimensional variation due to inter-element differences unrelated to this structure. The simultaneous processing of both sources of variation among a set of multidimensional visual patterns was examined. Similarity judgments to pairs of 14 polygons arising from two physical classes were scaled with the TORSCA nonmetric MDS procedure. No evidence was found for processing of dimensional variation in the varimax-rotated TORSCA solutions. However, Degerman rotation of TORSCA solutions led to recovery of both sources of variation. Confirmatory regression analysis based on physical measures of typal and dimensional variation among patterns indicated the appropriateness of the Degerman rotation.