Handedness in relation to direction and degree of cerebral dominance for language.

In so far as ear asymmetries on dichotic listening reflect cerebral dominance for language, the present evidence indicates a progressively decreasing incidence of left hemisphere dominance in right handed, mixed handed and left handed individuals. In the absence of a family history of sinistrality there are no indications that the degree of dominance is reduced in left handers or mixed handers when compared to right handers, nor that right hemisphere dominance is less securely established than left hemisphere dominance. Among strong left handers with a family history of sinistrality, however, ear difference scores are significantly smaller, indicating reduced lateralization or bilateral representation of language in such individudals. This applies equally in left dominant and right dominant left handers.