Asher sees Total Physical Response as directed to right-brain learning, whereas most second language teaching methods are directed to left-brain learning. Asher refers to neurological studies of the brains of cats and studies of an epileptic boy whose corpus callosum was surgically divided. Asher interprets these as demonstrating that the brain is divided into hemispheres according to function, with language activities cen¬tralized in the right hemisphere. Drawing on work by Jean Piaget, Asher holds that the child language learner acquires language through motor movement - a right-hemisphere activity. Right-hemisphere activities must occur before the left hemisphere can process language for production. Similarly, the adult should proceed to language mastery through right-hemisphere motor activities, while the left hemisphere watches and learns. When a sufficient amount of right-hemisphere learning has taken place, the left hemisphere will be triggered to produce language and to initiate other, more abstract language processes.