Early theory and research on hemispheric specialization.

This article provides an account of early theory and research on hemispheric specialization. It begins by tracing theory and research on localization of function that set the stage for the discovery of hemispheric specialization. After that, it describes the studies of Paul Broca, John Hughlings-Jackson, and others on hemisphere specialization and reviews some of the proposed explanations for the phenomenon. It then turns to the study of hemispheric specialization and mental illness, and it ends by identifying some of the linkages between theory and research from the past and the present.