Simultaneous and Successive Presentation of Elements of the Mueller-Lyer Figure and Chronological Age

Abstract

Optico-geometrical illusions may be dichotomized into those whose magnitudes decrease with an increase in chronological age (Type I) and those whose magnitudes increase with chronological age (Type II). The former illusions appear to be determined largely by stimulus variables and the state of the receptor system, and not at all by intellectual functions. The latter appear to depend upon the comparison of visual stimuli separated by space or time, such comparisons seeming to necessitate intellectual functioning. In this experiment the method of presentation of a Type I illusion was altered so that its parts were presented in succession rather than simultaneously. It was predicted that such alteration would reverse the direction of illusion, reverse its developmental pattern, and would produce a correlation with measured intellectual capacity, all of which would be characteristic of a Type II illusion. Ss were school children in Grades 2 to 5. All predictions were confirmed. The implications of the results for an overview of perception in general were discussed.