The cognitive consequences of illiteracy are studied by comparing adults who were not alphabetized for socioeconomic reasons to
controls who were alphabetized at adult age in alphabetic and non-alphabetic writing systems. Concerning language, both capacities
of conscious, explicit analysis of speech and of perceptual processing of spoken words are examined. Concerning the other aspects
of cognition, the following capacities are investigated: memory processes, problem solving, executive processes, semantic memory
and its organization, and visual perception and cognition.