title: Saliency metric for subadditive dissimilarity judgments of rectangles.
abstract: Previous findings that dissimilarity judgments for rectangles are strongly subadditive, that qualitative individual differences are always present, and that four-parameter psychophysical maps can reproduce the average ratings (Schönemann & Lazarte, 1987) are replicated. However, the present study in addition suggests that the metric for bounded response transformation, previously used to restore additivity of responses, has a modest effect on the fits of the psychophysical maps. The differential weighing of the coordinates already incorporates segmental subadditivity predictions into the maps. In fact, the psychophysical maps define a subadditive saliency metric that depends on assigning larger weights to larger coordinates. This constraint on the weights of these maps, together with the response times, allows us to identify a strategy shift when subjects respond to two classes of stimulus pairs: For rectangle-rectangle pairs, subjects center on the shape and size of the rectangles; for square-rectangle pairs, the focus is on height and width.
authors.affiliation: Purdue University, West Lafayette, Indiana.
authors.forename: A A
authors.initials: AA
authors.lastname: Lazarte
authors.forename: P H
authors.initials: PH
authors.lastname: Schönemann
mesh_terms: D000328:Adult; D001288:Attention; D004193:Discrimination Learning; D005260:Female; D005556:Form Perception; D006801:Humans; D008297:Male; D009949:Orientation; D011601:Psychophysics; D012858:Size Perception