Figural and semantic factors in change in the Ebbinghaus illusion across four age groups of children

Changes in the Ebbinghaus illusion across age groups have been studied with 80 children (ns=20) from 4 to 8 yr. old. The distortion, whose magnitude increases across age groups, depends on active cognitive comparative processes. In fact, if some cues make the geometrically identical inducing elements semantically different from the central one, the illusion decreases as older children develop conceptual categories. Across ages 4 to 8 years not only the magnitude of the illusion changes but also the interfering role of the taxonomic organization.