The effect of aging and rhythmic temporal structure during encoding on recognition memory: an EEG Study

Aging deficits in memory have long been established in the literature, however, little has been done to investigate how environmental factors can be used to ameliorate age related declines in memory functioning. Recent research in recognition memory suggests that increased temporal expectancy during encoding can benefit recognition memory at retrieval in a younger adult sample. The current study aimed to investigate whether the benefit to recognition memory, and associated neural processes, observed in young adults is also evident in normal aging. Unfortunately, due to national restrictions affecting data collection, no older participants were able to be tested. As such, the current project resolved to provide a proof of concept to inform an investigation of the originally intended scope. Ten young participants (M age = 23.5; SD = 2.22) were exposed to pictures of everyday objects in 3 rhythmic and 3 arrhythmic encoding blocks, after which they performed a recognition memory test containing previously studied and new objects. A clear trend suggesting better memory following rhythmic encoding was observed, but no significant difference between conditions emerged. Furthermore, analysis of relevant ERP components uncovered no old/new effect in relation to the LPC or the LFE. Conversely, the FN400 displayed an old/new effect. Thus, the temporal manipulation did not result in significant differences in recognition, but it should be noted that the study is underpowered. However, participants did display a good ability to discriminate stimuli, and in addition RT differences between correct and incorrect recognition judgements and an FN400 old/new effect suggest that the paradigm is effective and sensitive to processing differences between conditions. Recognition could be detected by the FN400 in the present experiment. However, trends in recognition ability between temporal structures suggest that an insufficient sample size is likely to have caused the lacking significant temporal effects. As such, the paradigm is appropriate for extension including a larger sample size and the planned comparison of age groups.