Attentional balance and intelligence

Recent studies of neuroimaging during cognitive tasks suggest that most tasks involve the activity of widespread areas in both cerebral hemispheres. In many cases, information must be shared between the two hemispheres. The coordination of these areas involves the brain's attentional networks. Unilateral brain damage often causes asymmetries in attention and reduced speed of processing. Based on these findings it was hypothesized that mental processing in normals will be more efficient when normal people can shift attention to either hemisphere with equal efficiency. Attentional balance was measured by the degree of asymmetry found during the covert visual-orienting task. Intelligence was measured by the Raven Standard Progressive Matrices. Data from two experiments suggest that low asymmetry in attention shifting is associated with higher intelligence.