Does the serial position effect identify those at risk for dementia? Findings from the Canadian Longitudinal Study on Aging.

OBJECTIVE: Subjective cognitive decline (SCD), or a self-perceived decline in cognition without objective cognitive impairment, is a potential predictor of Alzheimer's disease. However, summary-level scores on objective neuropsychological measures often fail to detect subtle cognitive changes in this population. The serial position effect (SPE), where individuals tend to recall items presented at the beginning (primacy) and end (recency) of a word list better than ones in the middle, may provide greater sensitivity. Although altered SPE patterns have been observed in Alzheimer's disease, SPEs remain understudied in SCD. METHOD: Using data from the Canadian Longitudinal Study on Aging, we examined cross-sectional and longitudinal SPE patterns and serial position ratio scores in older adults aged 60 years and above. Participants were categorized as controls, SCD-no worry, and SCD + worry based on self-report measures of SCD and related worry. SPE indices were derived from the Rey Auditory Verbal Learning Test. RESULTS: In cross-sectional analyses, the SCD + worry group had lower primacy recall than controls on both Rey Auditory Verbal Learning Test trials (immediate: b = -1.93; 5-min delayed: b = -1.89; ps < .01). In contrast, both SCD subgroups had higher recency recall on the immediate trial (SCD-no worry: b = 1.40; SCD + worry: b = 2.46; ps < .05) and higher recency ratios than controls (SCD-no worry: b = 0.07; SCD + worry: b = 0.08; ps < .001). Longitudinally, the SCD-no worry group experienced greater decline in primacy recall than controls across both Rey Auditory Verbal Learning Test trials (immediate: b = -3.05; 5-min delayed: b = -3.49; ps < .05). CONCLUSIONS: SPE patterns may capture subtle memory changes in SCD and could serve as sensitive markers for identifying those at elevated risk of future cognitive decline. (PsycInfo Database Record (c) 2026 APA, all rights reserved).