Arousal and memory: Effects of aging

These studies examine the influence of phasic and tonic arousal on memory performance in younger and older adults. Subjects in Experiment One were asked to learn a list of 25 simple line drawings during Session One and 24 drawings with a unique item (i.e., the critical event) in the center position (photograph of either a normal or starving child) during Session Two. Previous research has demonstrated that younger adults' memory for a critical event increases, while memory for items surrounding the critical event is disrupted, presumably because of phasic arousal elicited by the distinctive item. This phenomena had not been replicated with older adults. In this study, while both younger and older adults demonstrated increased recall of the critical event, only younger adults' recall for surrounding stimuli was disrupted. Younger adults also demonstrated greater disruption in memory when the photograph was subjectively more disturbing (i.e., emaciated rather than normal child), while older adults showed similar memory patterns for surrounding items regardless of the nature of the center item.; In the second study, state dependent learning was examined by manipulating physiologic arousal. Subjects either rested or exercised immediately prior to learning a modified version of the California Verbal Learning Test, and then engaged in either the same or the alternate activity immediately prior to delayed recall. Both younger and older adults showed clear state dependent learning effects, as well as increased semantic clustering, when in the same state at both acquisition and recall. Age by type of memory test interactions were found in both studies, with age differences on recall but not recognition tasks. No age by arousal state interactions were suggested; young and old were equally affected by state dependent learning, and neither group was affected by overall level of arousal during the learn or recall phase. Brain areas implicated as important in explaining the age differences and similarities found include the amygdala, frontal lobes, and hippocampus.