According to the associative deficit hypothesis, older adults experience greater difficulty in remembering associations between pieces of information (associative memory) than young adults, despite their relatively intact memory for individual items (item memory). Recent research suggests that this deficit might be related to older adults’ reduced availability of attentional resources – the reservoir of mental energy needed for the operations of cognition functions. The purpose of this Dissertation was to examine the role of attentional resources in associative deficit, and to explore encoding manipulations that might alleviate the deficit in older adults. In Study 1, young adults’ attentional resources during encoding of word pairs were depleted using a divided attention task. These participants showed an associative deficit commonly observed in older adults, and were less likely to use effective encoding strategies and recollection-based processes to support their memory in comparison to young adults under full attention. The resemblance in memory performance between young adults under divided attention and older adults suggests that lack of attentional resources might be a contributing factor in older adults’ associative deficit. In Study 2, participants’ resource load during encoding was reduced by learning individual items and their associations sequentially in two phases. Older adults in this condition showed equivalent memory performance to young adults, and were more likely to use effective encoding strategies and recollection-based processes than older adults in Study 1 who studied items and associations simultaneously. Finally, Study 3 employed a value-directed learning paradigm, in which participants studied high- and low-value word pairs. Older adults showed similar memory performance for both high- and low-value word pairs as young adults, without any signs of associative deficit. Assigning value to associative information might prompt older adults to prioritize associative encoding over item encoding, which benefits their associative memory. Taken together, these results suggest that depletion of attentional resources during encoding could impair associative memory. Furthermore, older adults’ associative deficit could be effectively alleviated with sufficient environmental support during encoding, such as when resource competition between item and associative encoding is minimized (Study 2) or when being guided to prioritize encoding of associations over items (Study 3).
A simulation of older adults’ associative memory deficit using structural process interference in young adults
