IMPORTANCE OF CONTEMPORARY SEQUENCES AND HISTORICAL PATTERNS ON BRAINRESPONSES ACROSS THE LIFE-SPAN

Brain and behavioral responses to infrequent but equiprobable, predict able (fixed) and unpredictable (random) targets were measured to test the hypothesis that a shift in focus from local to global (historical) events occurs across the life span. Memory of sequence was informativ e in the fixed condition because the occurrence of a target could be p erfectly predicted. Recalling the sequences contributed to the develop ment of global probability estimates in the random condition, but did not provide specific information about the occurrence of an event. A h ighly significant advantage was evident in brain and behavioral respon ses only in young and middle-aged subjects to predictable targets (i.e ., use of local information). Among elderly subjects, the event-relate d potentials and reaction times to predictable and random targets were indistinguishable. The relations of age and reaction time to P3 ampli tude were topographically discrete and consistent with earlier literat ure.