<p> The study concerns how human observers judge the relative position of successively presented points of light in an otherwise dark field. In particular, the possible role of involuntary head movements and binocular/monocular viewing conditions is considered. The data are analysed in terms of a mathematical model of the perceptual process which deals with short term memory for visual position. Contrary to previous suggestions in the literature, neither of the viewing variables proved to have a significant effect. In addition, the results provide a strong test of the theoretical model which appears to confirm the model's validity. The results of this study are shown to suggest a particular direction for future experimentation.</p> / Thesis / Master of Arts (MA)