Memory specificity in aging: Detrimental and beneficial effects of item similarity.

The similarity of incoming information can influence the precision with which older adults remember the details of past experiences. While similarity can reduce memory precision through interference at encoding or retrieval, leading to poorer item-specific memory and increased false memories, it may also enhance retrieval by serving as a cue that supports retrieval of item-specific information. The present study investigated how the effects of similarity vary depending on the time point of memory assessment. Older participants (N = 887, 60-88 years) from the Berlin Aging Study-II encoded word-picture pairs containing one, two, or four category exemplars and completed a recognition test either immediately or after a 7-day delay. Results showed that immediately after encoding, larger category size was associated with lower item memory, consistent with interference effects. However, during delayed recognition, larger category size enhanced item memory, suggesting that similarity acted as a "hook" supporting retrieval of item-specific information. Confidence ratings mirrored these patterns: Lower confidence accompanied correct retrieval from larger categories at the immediate test, whereas confidence increased with category size at the delayed test. False alarms to within-category lures increased with category size and with delayed retrieval, indicating the double-edge nature of category information. These findings suggest that while similarity can interfere with memory shortly after encoding, it may support retrieval over time by scaffolding item-specific retrieval through category knowledge. (PsycInfo Database Record (c) 2026 APA, all rights reserved).