The creation and reversal of the Müller-Lyer illusion through attentional manipulation

A configuration is presented in which both the overestimated and the underestimated portions of the Müller-Lyer illusion are embedded. In free viewing no distortion of length occurs; however, overestimation or underestimation illusions can be produced by simple manipulation of the attentional set, thus demonstrating one cognitive component in the formation of the Müller-Lyer distortion.