SIZE CONSTANCY AND ITS AFFECTING FACTORS: ANGLE OF REGARD AND SPATIAL DIRECTION OF STIMULUS OBJECT

The present study is an investigation on relating the degree of size constancy to the. angle and the spatial direction of the stimulus object in a short dark room. The other aim of the study is to find a concrete testinomy to the Geer & Zwaan's suggestion about the moon illusion. The experiment was carried out in a short dark room of 7 m. Two circular dim lights served as stimulus object: the standard stimulus was 6.5 cm in diameter, fixed at 200 cm away; the comparison stimulus was placed at varying distances and was variable in diameter. The presentation of the Sc (Comparison stimulus) was by the constant method. If the stimulus object was presented, the observer could find the artificial distance cues. The observers, eight university students, were instructed to compare the apparent size of Sc with Ss (standard stimulus) at varying distances under the four viewing conditions in terms of three categories. The experimental results found that the size constancy under the condition of viewing with the eyes looking upward was underestimated compared to that of viewing with the eyes looking in the primary position, and that the size constancy was more pronounced in the primary position than in the supine position.