The visual categories for letters and words reside outside any informationally encapsulated perceptual system

According to Pylyshyn, the early visual system is able to categorize percep tual inputs into shape classes based on visual similarity criteria; it is a lso suggested that written words may be categorized within early vision. Th is speculation is contradicted by the fact that visually unrelated exemplar s of a given letter (e.g., a/A) or word (e.g., read/READ) map onto common v isual categories.