Is Repetition Learning Preserved in Old Age? Insights from the Hebb Paradigm

Repetition learning has been frequently studied using the Hebb effect: Immediate serial recall performance improves for a memory list which is repeated amidst other, non-repeated lists. Previous research has suggested that older adults learn as well as younger adults in the Hebb paradigm. Because older adults show an age-related deficit in associative episodic memory, this suggests that learning in the Hebb paradigm is not driven by associative memory. In fact, it has been shown that learning sequentially presented lists through repetition is likely to be driven by a chunking mechanism, by which the whole list is integrated into a single unified representation. Here, we investigate age differences in the Hebb paradigm to determine the conditions under which repetition learning relies on associative episodic memory. We found that older adults learn at the same rate as younger adults in a standard Hebb paradigm with lists of letters. By contrast, Hebb repetition learning of pairwise associations of words was slower in older than in younger adults. Our results suggest that (a) repetition learning is only driven by associative memory when learning pairwise associations is required to solve the task, and (b) that older adults’ capability to learn from repetition is as good as that of younger adults whenever memory lists are presented in sequence. Thus, the process of chunk formation is largely preserved in old age, at least in the verbal domain.