Mirror-image discrimination among nonliterate, monoliterate, and biliterate Tamil subjects

In Danziger & Pederson 1998, the suggestion was made that the discrimination of left/right mirror images from non-reflected images in a part/whole judgment task correlates not just with degree of literacy, but also with the nature of the script in wich the subject is literate. This follow-up study directly addresses this hypothesis by comparing acceptance/rejection responses and the reaction time of these responses among Tamil speakers who were coded for type of literacy (nonliterate, literate only with Tamil script, literate with Tamil and Roman script). There was a reliable difference between the monoliterate and biliterate speakers in that biliterate Tamils were far more likely to reject mirror images than monoliterate Tamils. The critical difference between the monoliterates and biliterates is taken to be whether a graphemic distinction (i.e. a distinction which is symbolically meaningful) between left/right reflections has been acquired.