Length judgments in modified Mueller-Lyer figures

Abstract

In two experiments, subjects made line length matches and relative line length comparisons of a transverse line perpendicularly intersecting the midpoints of the center shafts of the Mueller-Lyer figures. The results indicated that the illusion of transverse line length occurs in a direction opposite to the illusion of shaft length; findings suggesting an asymmetry in the distortion of the space across the Mueller-Lyer figures were thus confirmed. The possible contribution of framing effects induced by the fins of the Mueller-Lyer figures in determining the illusion of transverse line length is discussed.