The effect of task difficulty upon the extent to which performance benefits from between-hemisphere division of inputs.
The means by which the two hemispheres coordinate processing of information are not well understood. By means of a tachistoscopic paradigm, we have shown repeatedly that performance is better when two conflicting tasks are presented to separate hemispheres than when both tasks are presented to a single hemisphere. The present study examines whether this effect is restricted to a specific range of task difficulty. Adult right-handers viewed two conflicting naming tasks by means of a tachistoscope. Task difficulty was lowered by reducing processing load (Experiment I: N = 32). Task difficulty was raised by projecting a visual mask 40 ms after offset of the visual displays (Experiment II: N = 10). At lower levels of processing load, dividing conflicting tasks between the hemispheres was beneficial, but not significantly so. At higher levels of load, and at either higher or lower loads with a visual mask, there were significant benefits associated with dividing conflicting tasks between the hemispheres. Three alternative explanations are discussed for the absence of an advantage associated with between-hemisphere division of inputs when task difficulty is reduced.
Merola
J L
JL
Psychology Department, Boston University, MA 02215.
Liederman
J
J
D001921:Brain / Q000502:physiology*; D004292:Dominance, Cerebral; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010470:Perceptual Masking; D013647:Task Performance and Analysis; D014794:Visual Fields