Spreading activation in episodic memory: further evidence for age independence

Seventy-two young (mean age = 25 years) and 72 old adults (mean age = 71 years) participated in an experiment that addressed the influence of episodic and semantic prime activation on speeded episodic recognition judgements. On each test block, subjects studied two paragraphs at their own pace to achieve a designated level of episodic recognition performance. Following the study period, subjects were presented a series of prime-target trials for speeded episodic recognition. The primes were either (a) episodically related to the target, (b) semantically related to the target, (c) episodically and semantically related to the target, or (d) episodically and semantically unrelated to the target. The stimulus onset asynchrony (SOA) between the primes and targets was either 200 msec, 600 msec, or 1000 msec to address age-related changes in the rate at which these different prime types influenced performance. The results indicated that, compared to young adults, the old adults (a) studied the paragraphs for a longer period of time, (b) responded to the targets more slowly, and (c) were less accurate in their episodic recognition decisions. Although there were these main effects of age, the young and old adults were influenced in a similar fashion by the different prime-target relationships and by the interactive influences of the prime-target relationships and SOA. Correlational analyses indicated that the pattern of priming effects was as similar across the two age groups as across two pseudo-groups that were matched on the age dimension. These results were viewed as further support for the notion that the characteristics of the spreading activation mechanism as reflected by prime-target manipulations are relatively stable across young and old adults.