UC Irvine

Brain and behavioral responses to infrequent but equiprobable, predictable (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 informative in the fixed condition because the occurrence of a target could be perfectly predicted. Recalling the sequences contributed to the development of global probability estimates in the random condition, but did not provide specific information about the occurrence of an event A highly significant advantage was evident in brain and behavioral responses only in young and middle-aged subjects to predictable targets (i.e., use of local information). Among elderly subjects, the event-related potentials and reaction times to predictable and random targets were indistinguishable. The relations of age and reaction time to P3 amplitude were topographically discrete and consistent with earlier literature. © 1993, Taylor & Francis Group, LLC. All rights reserved.