The Differences of Sensory and Motor Evaluations of the Müller-Lyer and Ponzo Illusions

Аннотация

Abstract. This experiments were designed to measure sensory and motor size judgements of the Müller–Lyer, the Ponzo and the Trapezoidal illusion. The touch screen was used to record the movements of the right and the left hands when the participants estimated the length of the horizontal lines in illusory context or without illusion. There were two types of tasks: memorization and reproduction. There was an illusory effect for movements of both the right and left hand, but there is less of an illusory distortion when the left hand was used. The explanation could be that different systems of representation are involved in the process underlying size estimation using the right and the left hands: based on a metric system of representation in the right hemisphere and a categorical representational system in the left hemeisphere. The size of the Müller-Lyer and Ponzo effects are different in memorization and reproduction tasks. The Müller-Lyer illusion exists in both situations whereas the Ponzo illusion generally exists only in reproduction task. This suggests that the two illusions have different underlying mechanisms. Keywords: sensory and motor size judgements, Müller-Lyer, Ponzo, right and left hand