Discriminating semantic from episodic relatedness in aging: The effects of response deadline and retrieval task
The ability of young and older adults to discriminate preexperimental (semantic) from experimental (episodic) associations was examined. Young and older participants first studied a list containing semantically related and unrelated word pairs. At test, word pairs were either intact pairs (both unrelated and related), rearranged pairs, or completely new pairs. Rearranged pairs were either unrelated pairs whose members were originally studied in unrelated pairs, unrelated pairs whose members were originally studied in related pairs, or related pairs whose members were originally studied in unrelated pairs. Participants made either associative recognition judgments (Experiments 1a and 1b) or semantic relatedness judgments (Experiment 2). Both long and short response deadlines were used to trace the time course of retrieval in associative recognition and semantic relatedness judgments.
For associative recognition judgments, both young and older adults benefited from semantic relatedness, leading to higher hit rates for related compared to unrelated intact pairs. At the long response deadline, older adults' performance on related intact pairs matched that of young adults. Also, both young and older adults demonstrated lower false alarm rates to unrelated rearranged lures whose members had originally been studied in related pairs. Presumably, both young and older participants were able to recall the originally studied, related pair-mate and use this information to reject these lures---demonstrating utilization of recall-to-reject processes in both age groups.
In making semantic relatedness judgments, both young and older adults benefited from episodic associations, leading to more correct "related" responses to related intact pairs compared to related rearranged pairs---an episodic priming effect.
Consistent with a decline in recollection with age, an age deficit was found in associative recognition, but similar patterns of age effects were not seen in the semantic judgment task in which recollection was not required. This asymmetry is discussed in the context of arguments about dedifferentiation in old age, implications for the associative deficit hypothesis of cognitive aging, and models of semantic and episodic memory.