Similarity judgments of patterns and maps

Abstract

An algorithmic technique is described for generating from a common prototype three populations of forms (dots, open forms, and polygons) having different configurational properties. Within each population, subjects rated the similarity between standard stimuli and 20 transformations of these stimuli. The stimuli were represented to the subjects as abstract patterns or as maps. High rank·order correlations were obtained between the ratings given to the various transformations in each form population and in the pattern and map conditions. These correlations led to two conclusions: (1) there was ecological validity in the stimulus factors that influenced similarity judgments in the three form populations, and (2) subjects used analogous processes when making similarity judgments in tasks focusing upon pattern perception and spatial reference systems.

Patterns of perceived similarity cannot be generalized from long to short exposure durations and vice versa

“…Inspection time was varied in a between-subject design. As in the Halpern et al (1979) study, it was found that the variables of form type (dots,lines, polygons) and axis of rotation (x, y, z) had no effect on perceived similarity in the long exposure conditions. However, when inspection time was limited to 150 msec, both variables had a substantial impact.…”

“…More specifically, at very short exposures (150 msec), which are rarely used in ratings studies, perceived similarity is very sensitive to variables that have no effect at longer exposures. This finding undermines the common practice of selecting stimuli for use in reaction time and other experiments with brief exposure durations on the basis of similarity ratings gathered under free inspection conditions.The stimulus patterns we used were taken from a study by Halpern, Fishbein, and Warm (1979) and are shown in Figure 1. These investigators were interested in the problem of representativeness in the perceived similarity of patterns.…”

“…The stimulus patterns we used were taken from a study by Halpern, Fishbein, and Warm (1979) and are shown in Figure 1. These investigators were interested in the problem of representativeness in the perceived similarity of patterns.…”

“…The stimuli, adapted from Halpern, Fishbein, and Warm (1979), were randomly generated dot patterns and line drawings and polygons generated from the dot patterns. Inspection time was varied in a between-subject design.…”

“…Dot patterns were generated by random selection of cells in an 8 x 8 matrix, while corresponding line and polygon patterns were created from the dot patterns by the application of specific rules (see Halpern et al, 1979, for a more complete description). Thus, a particular set of stimulus information is realized in three different graphic forms.…”