Learning to Read Enhances the Ebbinghaus Illusion

We examined whether literacy influences the Ebbinghaus illusion. Illiterate, ex-illiterate and literate adults performed a size-decision task on circles surrounded by inductors or without-inductors. Readers performed worse than non-readers with inductors, i.e., larger illusion, but similarly without-inductors. Literacy has spill-over effects on size processing with stronger influence by the surrounding.