Age Differences in Flexibly Binding Memory of What, When and Where

Experiences are multimodal and often involve what, when and where aspects. Past researchin young adults has shown that a core function of memory is to learn flexible associative structuresconnecting all aspects. We investigated how aging affects multimodal memory associations and retrievalflexibility of complete or partial events. In two experiments, 63 younger (18–35 years) and 50 olderadults (65–85) completed a spatio-temporal object memory task in which they encoded object sequencesappearing at different screen locations over repeated exposures, and then retrieved either object orlocation sequence, or complete object-location sequence. Memory for object sequences was best, followedby location sequences and object-location combinations in both age groups, while age differences werelargest during complete sequence retrieval. Performance dependencies across retrieval tests showed bothage-groups used multimodal binding to scaffold sequence memory, such that even pure object sequenceretrieval relied partly on location knowledge, and vice versa. Younger adults showed greater flexibility inmodulating binding strength depending on retrieval demands, compared to older adults. Computationalmodeling demonstrated a two-system model best captured performance in both age groups, assumingparallel learning of sequential transitions within each dimension and bi-directional binding associationsbetween dimensions. Younger adults relied more on object-location binding associations than transitionlearning, while older adults showed equal reliance on both learning systems. This suggests that age-related impairments in sequential memory are partly driven by reduced memory binding and flexibilityin memory use, providing novel insights into how memory for what, when and where changes with aging.