Lateral asymmetries in attentional priming during a semantic and a visuospatial task

This study rests the hypothesis that lateral cueing of attention activates the contralateral hemisphere and also that performance on a semantic and a visuospatial task will differentially be affected depending on the visual f ield (right or left) to which attention was drawn. In an experimental setti ng, 68 subjects performed both a semantic and a visuospatial discriminating task, whereby visual priming signals unbeknownst were presented to either the left or the right visual field. Tor the semantic task (which is believe d to engage primarily the left hemisphere) priming signals enhanced perform ance more when they were presented to the right visual field. For the visuo spatial task, no difference was found between priming signals presented in either visual field. While there may be several alternative explanations fo r the observed difference in the effects of the priming signals presented t o different visual fields, the importance of separating the components inhe rent in the tasks is stressed. While the process of derision-malting may in volve different relative activation of the two hemispheres, depending on wh ether the stimuli are semantic or visuospatial in nature, performance on th e rash also involves manual coordination which will depend especially on mo tor activation in the left hemisphere.