| This thesis presents an evaluation of neurophysiological and behavioral measures of attention in children of varying ages. It is widely held that selective attention and sustained attention are essential to the development of cognitive abilities. Behavioral performance and event-related potentials (ERPs) were studied in 24 children between 8 and 18 during a dichotic listening task. Behavioral performance measures included perceptual sensitivity (;On behavioral measures, older children showed greater perceptual sensitivity (d') and faster reaction times. Performance declined over time in the difficult discrimination (Irregular) condition, but at the same rate in younger and older children.;PRN in the easier (Regular) condition was larger for younger than older children. In the younger group, N1 was absent despite the presence of PRN and MMN, which occur in the same latency range. Effects of sustained attention were seen for N2 and PRN, with the younger children showing a tendency for reduced amplitude across time whereas the older children's amplitude remained stable. For P3, there was also a decrease in amplitude early in the block, but it was similar for both age groups.;The automatic registration of novelty was influenced by maturation during both task conditions, with younger subjects demonstrating a consistently greater MMN than older subjects. Target selection, as demonstrated by P3, was not influenced by age.;These findings suggest that maturation of attentional processes is complex, with dramatic age differences seen on some measures. The data indicate that electrophysiological measures may be useful in elucidating mechanisms of attentional deficits in clinical populations. |
