title: Subtraction in addition to addition: dual task performance improves when tasks are presented to separate hemispheres.
abstract: This research links neuro- and cognitive psychology by asking whether performance of two concurrent cognitive tasks is facilitated by presentation of each task to a different cerebral hemisphere. Subjects were required to perform two arithmetic problems which were presented simultaneously. One problem required addition; the other subtraction. In Experiment I, briefly exposed numbers were exposed for 100 ms and were arranged so that a digit at fixation had to be added to a top number and subtracted from a bottom number. In Experiment II, the numbers were reversed so that the addition task was below the subtraction task. During Bilateral/bihemispheric trials, the addition problem was presented to one visual field and the subtraction problem to the other visual field. During Unilateral/single hemisphere trials, the addition and subtraction problems were projected to only one visual field. Results indicated that a higher proportion of problems were correctly solved during the Bilateral/bihemispheric trials than during the Unilateral/single hemisphere trials. These data suggest that dividing simultaneous inputs so that each hemisphere is confronted with a task requiring only one kind of cognitive operation facilitates performance, perhaps by minimizing intertask interference. This study illustrates one kind of hemispheric cooperation which facilitates dual task performance.
mesh_terms: D002540:Cerebral Cortex / Q000502:physiology; D003071:Cognition / Q000502:physiology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008433:Mathematics; D011340:Problem Solving / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014794:Visual Fields