Competition for Left Hemisphere Resources: Right Hemisphere Superiority at Abstract Verbal Information Processing.

Abstract : In this paper, we present a direct test of a multiple-resources approach to resource allocation in information processing, in which the two cerebral hemispheres are assumed to have separate, limited-capacity pools of undifferentiated resources. Five right-handed men were selected on the basis of having manifested a RVF-LH superiority for processing the stimuli used in each of two tasks that were to be performed concurrently in the main experiment. We then measured both single and dual-task performance on the tasks, which were a centrally-presented verbal memory load, and a nonsense syllable naming task in which the syllables were presented to either visual field. Subjects were paid according to their accuracy during both single and dual-task trials; on the latter, the payoff ratios were varied, to induce them to allocate more attention to either the memory task, the visual field naming task, or to both equally. In our approach, the two types of visual field trials are treated as two different dual-task situations. Right and left visual field trials of the naming task combined with the verbal memory load constitute, respectively, cases of complete or partial overlap in demand for left hemisphere resources. Therefore, on RVF dual-task trials, left hemisphere resources should be more scarce than on LVF trials. Under moderate to heavy memory loads, subjects who had shown large RVF single-task performance advantages for naming nonsense words showed larger performance decrements on RVF trials than on LVF trials in the dual-task situation, such that both naming task and memory performance was now superior when the naming task stimuli were presented to the left visual field.