Multiple resources and brain laterality

Two studies tested the multiple resources model of information processing using tachistoscopically lateralized input. In Exp. 1 37 normal, dextral subjects, 18 men aged 18/21 yr. and 19 women aged 18/22 yr. responded manually to a visuo-spatial and verbal dual-task presented simultaneously to left and right brain or nonlaterally. Both men and women tended to have superior performance with coherent lateral input, however, differences in task difficulty and the possibility of a left-to-right scanning advantage with lateral input made interpretation of the data tenuous. In Exp. 2 the difficulty of the two tasks was more equal and a third viewing condition, having noncoherent lateral input, was included. Normal, dextral subjects, 10 men aged 18/21 yr. and 10 women aged 19/21 yr. were tested under all three viewing conditions. Both men and women had superior performance with coherent lateral input compared to the other two conditions. The results led to speculations that each hemisphere has unique pools of resources, that the resources of one or both hemispheres may be functional in processing a given task, and that in dual-task situations the brain operates most efficiently and accurately with direct access of appropriate tasks to each hemisphere.