Top-down modulation of early selective attention processes in children

It has been demonstrated in adults that attention can modulate very early s tages of perceptual/cognitive processing, but it has not been determined if this capacity for modulation develops with age. We investigated early atte ntional processes in parallel and serial visual search tasks in 40 children 7-12 years old, using event-related potentials (ERPs). Two single-feature pop-out tasks were used to assess parallel processing; a conjunction of fea tures task was used to study serial processing. There were significant decr eases in latencies with age for the peaks measured [posterior P1, N1 and an terior P2 (P2a)]. P1 and N1 latency effects also varied with trial type and were consistent with top-down modulation of processing, which differed beh veen the parallel tasks. P2a amplitude for the hit trials decreased with in creasing age for the colour and serial tasks. Increasing R > L hemispheric asymmetries with age in P2a amplitude were seen on non-target trials for th e size and serial tasks only, reflecting serial processing. These data demo nstrate that developmental changes in visual selective attention for early stages of processing are continuing through childhood, and that there is to p-down modulation at these latencies in children. (C) 2000 Elsevier Science B.V. All rights reserved.