THE PERCEPTION OF LUMINOUS MULLER-LYER FIGURES AND ITS IMPLICATIONS FOR THE MISAPPLIED CONSTANCY THEORY

Views concerning the M-L (Muller-Lyer) illusion appear to lead to two different predictions and it is the purpose of the communication to attempt a clarification of the ambiguity. It is possible to give two misapplied size constancy interpretations and these are: (a) The two shafts are perceived as parts of the overall configuration, and the fin 'perspective' and constancy scaling produce the distortion. That is, they are seen of different length because of the relative 'distance' effect together with the equality of retinal size. This would apply equally well to the perception of one M-L figure relative to a shaft minus fins, i.e. a straight line. (b) The shafts are independently distorted by virtue of the 'perspective' effects of their respective attached fins. That is, constancy scaling triggers a phenomenal distortion in each shaft and any 'distance' effect only occurs between each shaft and its attached fins. (Author)
Revision of report dated 17 Jan 68.