THE ABILITY OF UNTRAINED OBSERVERS TO MATCH VISUAL FORMS THAT ARE SLIGHTLY DISPARATE IN CONTOUR

摘要

The present report describes an exploratory study of the ability of observers to match, by a method of overlay, slightly disparate imaginary contours defined by three points each. Twenty-two subjects matched 100 pairs of contours, each formed by points plotted by random decision. Subjects were scored in terms of the discrepancy of location of the centers of mass of the two contours.nThe mean error (discrepancy) for all subjects in both the x and y coordinates was 2.9 mm. The mean absolute or circular error was 4.1 mm. The total display was about 76 sq. mm., so relative to the total display, errors were small. Individual differences were large, and, in part at least, seemed to be associated with degree of sophistication about the principle of least squares. A visual inspection of the pairs of forms associated with high circular error compared with those associated with low circular error led to the conclusion that discrepancy in shape of contour was the important factor. A numerical index reflecting in part shape of contour yielded a difference, borderline in significance, between high and low error producing forms. Thus, there is tentative evidence that shape discrepancy is a factor associated with magnitude of circular error.