Length illusion induced by contours?

Abstract

In psychophysical experiments, the stimuli with uniformly filled or outlined rectangles of fixed duration were used; various combinations of the rectangles with the regular sequences of filling stripes were also taken. It was demonstrated that the superposition of the stimuli did not change the illusion strength noticeably. The results obtained in the study support the suggestion that the filled interval overestimation in the Oppel-Kundt stimulus may be related to spatiotemporal integration along a continuous path of neural excitation evoked by the real and illusory contours of the filling.