Longitudinal Data Indicate That Hemispheric Independence Increases During Early Adolescence

Hemispheric cooperation is traditionally thought of as the ability to share information between the hemispheres. In addition to hemispheric sharing, cooperation between the hemispheres may involve hemispheric shielding. This requires inhibition or restriction of information rather than sharing of information and enables the two hemispheres to work with minimal interference. Results of our longitudinal study suggest that the ability to use the two cerebral hemispheres as relatively independent work stations undergoes an important developmental transition during early adolescence. This study was a follow-up of 65 of 120 children from a previous study by Merola and Liederman (1985). The mean ages of the children were 12.0 years, 13.9 years, and 15.9 years at follow-up. Results indicated that (a) almost all the children who could not use their hemispheres independently at age 10 were able to do so at age 12.0, (b) almost all the children with this ability retained it 1 1/2 years later, and (c) this developmental transition was only marginally related to the onset of menarche in females.