Pr. Delucia, A QUANTITATIVE-ANALYSIS OF ILLUSION MAGNITUDE PREDICTED BY SEVERAL AVERAGING THEORIES OF THE MULLER-LYER-ILLUSION, Perception & psychophysics, 53(5), 1993, pp. 498-504
This article describes a quantitative method to evaluate several avera
ging (i.e., confusion and assimilation) theories by comparing predicti
ons of the absolute magnitude of the Muller-Lyer (ML) illusion with re
sults of previous studies of the composite ML figure. The magnitude of
illusion was best predicted by Davies and Spencer's (1977) theory and
by integrative field theory (Pressey & Pressey, 1992). Furthermore, w
hen the ML figure was at the point of subject equality, the average of
shaft and intertip distances, and the configural dimensions proposed
by Davies and Spencer, were most frequently closest to being equal in
the apex-in ML and apex-out ML. Results indicate that a comparison of
predicted and reported absolute magnitudes of the ML illusion can prov
ide quantitative criteria to distinguish and evaluate averaging theori
es of the ML illusion.