Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Chris Koronakos

Second Advisor

Dr. Malcolm Robertson

Third Advisor

Dr. Fred Gault

Access Setting

Masters Thesis-Open Access


A selective review of functional and anatomical hemispheric asymmetries in humans confirms the doctrine of hemispheric specialization. However, the post-insult phenomenon of recovery of functions challenges theories that posit too strict a correspondence between anatomical structures and functions. Follow-up studies on hemispherectomized and hemidecorticated patients, who later recovered language, support a hypothesis of hemispheric redundancy, rather than "invariant" hemispheric specialization for language. Thus, through an evolutionary selection process, the brain may have developed as two potentially similar organs. Neuropsychological research on recovery phenomena is criticized as neglecting environmental contributions to recovery. Several models of hemispheric specialization are compared with recovery phenomena, although no best model is identified. Finally, ontological, methodological, and epistemological reduction are defined and used to evaluate the assumptions of neuropsychologists and behavioral psychologists. It is argued that reduction to only one methodological level of analysis may exclude other valid theories of organismic functioning.