Hemispheres as independent resource systems: limited-capacity processing and cerebral specialization.

In this article, we develop as framework for understanding how cerebral specialization of function contributes to the flexibility of human information processing. We propose that the left and right hemispheres together form a system of two mutually inaccessible and finite pools of resources. Further, we propose that these two types of resources cannot be made available in different amounts at any given time. This framework is essentially a special case of a multiple-resources model of limited-capacity information processing. It accounts for a broad range of data from experiments involving perceptual and cognitive information processing, control of motor performance, and changes in electrical activity of the brain. It also provides insights into why the cerebral specialization literature has been plagued with problems that have made theorizing so difficult. In addition, the theory provides insights into mechanisms that might be responsible for patterns of task interference that are not easily handled by an information-processing model in which processes compete for supplies from a single pool of undifferentiated resources. Thus, the framework we are proposing has important theoretical and methodological implications for researchers in both divided attention and cerebral specialization.