Orienting and memory to unexpected and/or unfamiliar visual events in children and adults

For children, new experiences occur very often, and learning to differentiate between old and new events is a fundamental process necessary for appropriate reactions to stimuli. Thus the present study is concerned with maturation of brain responses to repeated novel events. We examined the effect of repetition of familiar (meaningful) and unfamiliar (meaningless) symbols on the event-related-potentials (ERPs) recorded during novelty oddball and recognition memory tasks from children, adolescents and young adults. During the novelty oddball task, repetition of the familiar symbols elicited a reduction in the novelty P3 in the ERPs of all age groups, while repetition of the unfamiliar symbols elicited a reduction in novelty P3 amplitude only in children. As expected, recognition memory performance improved with age and was better for familiar than unfamiliar symbols. For all age groups, ERPs to correctly recognized familiar old symbols elicited a larger positivity than ERPs to correctly identified new symbols, indicating a reliable memory effect. However, ERPs to unfamiliar old and new symbols did not differ in adults and adolescents but did differ in children. The data suggest that children process familiar visual symbols in a similar fashion to that of adults, and that children process unfamiliar symbols differently from adults.