The search for meaning: Age-related differences in the semantic N400 effect for picture pairs are unrelated to semantic benefits in episodic memory.

Abstract

Older age is characterized by attenuated episodic memory but intact semantic memory. At the same time, online semantic processing, particularly the prediction of lexical information, is attenuated, as reflected by a smaller event-related potential N400 effect for expected versus unexpected items. Previous research focused on semantic processing of verbal materials. However, we aimed at investigating not only age-related differences in the semantic processing of pictorial materials but also the relationship between such age-related differences and associative memory performance. Using picture pairs, we investigated whether age-related differences in online semantic processing, as manifested in the N400, are reflected in a behavioral measure of semantic processing (i.e., perceived semantic congruency) and, in addition, transfer to associative episodic memory. Younger and older adults studied sequentially presented object pairs with and without semantic relationships (e.g., a bathtub followed by a rubber duck, or a pillow followed by a punch, respectively). Their task was to judge the object pairs' semantic congruency. Thereafter, an associative memory test was conducted, in which participants had to discriminate between intact, recombined, and new object pairs. In the study phase, younger adults showed the expected N400 attenuation effect for semantically related pairs. For older adults, this effect was reduced, even though there was no difference between both age groups either in the magnitude of the semantic congruency judgments or in the behavioral congruency effect. Furthermore, both age groups showed highly similar benefits for semantically related pairs in the ensuing associative memory test. In conclusion, older adults seem to rely more on bottom-up stimulus-driven integrative processes instead of applying top-down predictive processes initiated by preactivated semantic knowledge. Furthermore, older adults' online semantic processing seems to be decoupled from the processing that results in associative memory benefit from semantic relations. (PsycInfo Database Record (c) 2026 APA, all rights reserved).