How retrieval process mechanisms change with age: exploring individual differences in free recall

This study examined age differences in retrieval using a single-list free recall paradigm. Younger and older adults performed the Word Recall test and differences in the delayed recall performance were explored. A similar pattern of retrieval dynamics was found with a larger primacy effect for both groups and a reduced temporal contiguity effect for older adults relative to the younger group. Significant differences were found when comparing the semantic memory network structures, with older adults presenting a less flexible and small-world-like structure. The third set of analyses explored subgroups of participants implementing idiosyncratic strategies and their impact on recall accuracy. Two subgroups relying on diverted processes from the average data were found for young and older adults, and the subgroup adopting non-temporal associations presented subtle differences among the two age groups. The participants that adopted temporal associations in a forward direction presented the highest recall performance compared with other strategies. We concluded that a reduced ability to reinstate temporal context information to guide retrieval and differences in semantic memory network structure account for deficits in episodic memory observed in older adults. This study provides evidence that the principles of memory search may not be universal as subgroups of participants adopting idiosyncratic strategies were revealed.