The Role of Eye Movements in the Perception of the Horizontal—Vertical Illusion

An experiment examining the role of eye movements in the determination of magnitude of the horizontal—vertical illusion (HVI) was performed by presenting the stimulus figures in conditions where eye movements or tendencies to eye movements were eliminated (i.e. presenting small figures tachistoscopically). The major result was that the illusion occurred within these conditions, indicating that eye movements do not play a major role in the production of the HVI. However, the finding that the magnitude of the HVI was positively affected in the conditions where tendencies to make eye movements were possible suggests that they exert a secondary role.