The processing of ambiguous words without context: Semantic activation, inhibition, selection and controlled retrieval in younger and older adults

This study investigates how healthy aging affects four core semantic memory processes: activation, inhibition, selection, and controlled retrieval. Two experimental paradigms were adapted in French to assess these mechanisms: a Lexical Decision Task (LDT) using ambiguous and monosemic words to examine automatic activation and inhibition, and a Cue-to-Target Association Task (CTTAT) to evaluate executive processes such as selection and controlled retrieval. For this purpose, 100 older (66.94±4.49) and 75 younger (26.64±5.87) adults were tested. Results from the LDT showed that both younger and older adults benefitted from semantic priming when processing dominant meanings and monosemic associates. In contrast, subordinate meanings and unrelated targets produced slower responses, suggesting the involvement of inhibitory mechanisms. These effects were consistent across age groups, indicating preserved early-stage activation and inhibition with aging. In the CTTAT, results showed that participants were more accurate when associating based on perceptual features than on overall meaning. While older adults preserved controlled retrieval abilities, they showed vulnerability selection process, especially in the presence of semantic distractors. Overall, the findings indicate that aging selectively affects semantic selection, whereas activation, early inhibition, and controlled retrieval remain largely intact. Together, these findings challenge global decline models of cognitive aging by showing selective effects on interference control. This work offers an integrated framework for assessing semantic control across the lifespan and lays the groundwork for future research on the interplay between automatic and controlled processes in semantic memory.