Through the Looking Glass: Literacy, Writing Systems and Mirror-Image Discrimination

A part/whole judgment task was administered to adults in ten different language communities around the world. Participants were instructed to treat two-dimensional abstract line figures differently from the left/right mirror-image reflections of the same figures. The data support the proposal that sensitivity to this kind of mirror-image contrast is acquired: Literate individuals generally were better able to operate in terms of this distinction than were non-literate participants in the study. Contrary to this general pattern, however, Tamil literates as well as non-literates often treated the left/right mirror-image reflections as non-reflected figures, despite the training to treat them differently. The difference between the Tamil literates and the literate individuals in the other language communities sampled may reflect the fact that mirror-image contrasts are used to different degrees in their respective scripts.