Can mirroring reveal image distortion? Illusory distortion induced by mirroring.

Artists claim that they can find unwanted distortions in their works easily by checking mirror images, suggesting that our sensitivity to distortion is different between normal and mirror images. In this study, participants observed distorted faces in which the left eye was displaced vertically, and judged which of the eyes was higher in both normal and mirror images. The results suggest that mirroring changed the perceptual definition of distortion, rather than sensitivity to it. It is concluded that the distortions that were 'detected' in the mirror images were illusory distortions induced by mirroring. A similar effect was also observed when the images were tilted by 45 degrees clockwise or counterclockwise.