Comparison of the Wings-in, Wings-out, and Brentano Variants of the Mueller-Lyer Illusion

Abstract

Explored illusion magnitude relationships between the Brentano Mueller-Lyer figure and its 2 component parts, the wings-in and the wings-out distortions. Exp 1 with 24 university students used a within-observer design, and Exp 2 with 70 university students used a between-observer design. Results indicate that the traditional measurement of illusion magnitude in the Brentano figure was best predicted by measurements of its underestimation rather than its overestimation component. Both experiments confirmed the close association between the Brentano figure and the wings-in component. Wings-out scores were not good predictors of Brentano illusion magnitude. Decrement training on the figure generalized to the wings-in but not the wings-out figure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)