DIAMOND-WINGED VARIANTS OF THE MULLER-LYER FIGURE - A TEST OF VIRSU (1971) CENTROID THEORY

Diamond-winged variants of the Muller-Lyer figure were used to test pr edictions of Virsu's (1971) theory of the Muller-Lyer illusion based o n efferent readiness for eye movements toward the figure's center of g ravity. A Muller-Lyer figure with diamond-shaped wings resulted in a g reater center-of-gravity distance than the corresponding, conventional Muller-Lyer figure, but fin length and the rest of the figure remaine d constant; in Virsu's study, fin length and center-of-gravity distanc e covaried. Results were consistent with Virsu's data when we used the stimulus conditions that he reported. Results from a wider range of s timuli challenge Virsu's theory, and thus are consistent with the conc lusions of Brigell, Uhlarik, and Goldhorn (1977).