| This dissertation investigates self-monitoring processes in the two cerebral hemispheres. A series of experiments in which performance feedback is presented to the left and right hemispheres during lateralized tasks examines the lateralization of metacognitive function. Several manipulations involving the type of cognitive task being monitored, the visual field of presentation, and the type of feedback stimulus presented show that the two hemispheres differ in their ability to process performance feedback. Results from lexical decision support a right hemisphere monitoring advantage in that task which depends on the type of feedback stimulus. In an object decision task, however, there is a different reaction to lateralized feedback, with performance affected most strongly when feedback is presented to the left hemisphere. Behavioral data are combined with functional magnetic resonance imaging and testing of split-brain patients to further elucidate the neural mechanisms of hemispheric monitoring. Split-brain patients were unable to correct their errors with either hemisphere, suggesting that interhemispheric communication may be necessary for error correction. Neuroimaging data indicate that feedback processing recruits neural networks for sensorimotor integration. Taken together, these results show that self-monitoring in the hemispheres is a complex, multi-faceted phenomenon that involves both interhemispheric independence and cooperation. |
