Is the right hemisphere literate?

Abstract

Coltheart (1980, 1983) has proposed that in the typical right-handed, left-hemisphere-dominant individual, the right hemisphere is, with limitations, literate. The primary skill of this right-hemisphere reading system is thought to be comprehension of printed words, especially concrete/imageable words; its failings are thought to include the following capacities: converting an orthographic code to a phonological one, dealing with abstract words, and distinguishing amongst semantically related words. Coltheart argues that the reading performance of deep dyslexic patients derives from the right-hemisphere reading system. His evidence for this proposal involves the claim that in reading-related tasks with orthographic input lateralised to the left visual field, both split-brain patients and normal subjects behave like deep dyslexics. We review and criticise this evidence.