There are a variety of ways of exploring the brain basis of psychological abilities such as visual attention. One of these approaches is to study how the postnatal development of cortical circuits gives rise to the onset of components of visual attention in the human infant. Due to the importance of visual attention in early infancy, it is evident that this approach may also be of clinical benefit. Furthermore, an understanding of the relation between postnatal cortical development and the emergence of cognitive abilities would clearly be a major advance for both developmental psychology and cognitive neuroscience. This research program is designed to test predictions of Johnson's theory about the relation between cortical maturation and the development of visual attention. This theory uses developmental neuroanatomical evidence to predict the sequence in which certain cortical circuits become functional. Since these circuits are thought to subserve components of visual attention, this allows predictions to be made about their developmental sequence. In human infants between 2 and 6 months of age these predictions will be tested by studying performance in certain tasks known to be specifically sensitive to the functioning of these cortical pathways. In addition, new "marker tasks" will be developed to make possible the investigation of "covert" visual attention i.e. shifts of attention that are independent of eye movements. Finally, work will be done on developing a standardized infant visual attention screening test. This test will subsequently be used in conjunction with neuroimaging techniques to investigate directly the neural basis of visual attention during infancy.
