Abstract:

The current study investigated the age differences in repetition priming of studied or new objects in a delayed-matching-to-sample task involving common objects. Prior to matching task, older or young participants intentionally studied a set of object pictures. For the matching task, a trial began with the presentation of two sample pictures (both were studied objects or both were new objects), then followed by twelve successive test pictures. The test pictures were classified into four types: studied match, new match, studied non-match, new non-match. Each types of test picture were repeated for three to four times within each trial. Participants were instructed to judge whether each test picture match one of the sample pictures or not as quickly and as accurately as possible. The results showed that older adults were generally slower than young adults in response, and both older and young participants respond faster to matches than to non-matches. RTs to studied matches were faster than to new matches, but RTs to studied non-matches were slower than to new non-matches for both older and young adults. Moreover, both older and young adults showed repetition effect for matches, with reduced repetition effect for non-matches. Repetition effect was reduced over times, and was differentiated between older and young participants. Importantly, while young adults showed no repetition effect for studied non-matches, older adults were significantly longer in response to repeatedly presented studied non-matches. These results demonstrated that implicit repetition effects for objects in older and young adults were affected by previous experiences with these objects. Repeatedly presented non-matches induced higher familiarity and caused difficulty for older adults in rejecting them, but this familiarity did not affect young adults.

Key words: explicit memory, implicit memory, repetition priming, delayed-matching-to-sample task, older adults