Task demand influences relationships among sex, clustering strategy, and recall: 16-word versus 9-word list learning tests

Objective: We compared the relationships among sex, clustering strategy, and recall across different task demands using the 16- word California Verbal Learning Test-Second Edition (CVLTII) and the 9-word Philadelphia (repeatable) Verbal Learning Test (PrVLT). Background: Women generally score higher than men on verbal memory tasks, possibly because women tend to use semantic clustering. This sex difference has been established via word-list learning tests such as the CVLT-II. Methods: In a retrospective between-group study, we compared how 2 separate groups of cognitively healthy older adults performed on a longer and a shorter verbal learning test. The group completing the CVLT-II had 36 women and 26 men; the group completing the PrVLT had 27 women and 21 men. Results: Overall, multiple regression analyses revealed that semantic clustering was significantly associated with total recall on both tests' lists (P<0.001). Sex differences in recall and semantic clustering diminished with the shorter PrVLT word list. Conclusions: Semantic clustering uniquely influenced recall on both the longer and shorter word lists. However, serial clustering and sex influenced recall depending on the length of the word list (ie, the task demand). These findings suggest a complex nonlinear relationship among verbal memory, clustering strategies, and task demand.