A double-edged sword: the role of prior knowledge in memory across the adult lifespan

Objectives: This study aims to investigate the role of prior knowledge on memory across the adult lifespan, and specifically examines the effects of two material properties: congruency – whether the material is congruent with people’s prior knowledge, and ambiguity – whether the material is ambiguous to interpret based on prior knowledge. Method: A total of 273 participants (aged 22-70 years old) completed an incidental memory task online. Participants were shown pictures depicting an object in a scene and judged if the object was likely or unlikely to be in the particular scene. Later, in the recognition test, participants were asked to identify if the picture was presented earlier. The pictures were manipulated to have varying levels of congruency, meaning that some depicted likely object-scene pairs and some unlikely, and varying levels of ambiguity, meaning that some were more ambiguous to judge than others. Mixed effects logistic regressions examined the effect of age, age2, congruency/ambiguity, and their interactions on memory.Results: The object-scene pairs perceived as congruent had both higher hit rates and higher false alarm rates than incongruent ones, especially in middle-aged and older people. Higher ambiguity was also related to both greater true and false memory, independent of age. Finally, the effect of ambiguity only emerged when the pair was perceived incongruent. Discussion: The results suggest that knowledge improves recognition but also induces false memories, particularly in middle-aged and older people, suggesting a double-edged role in memory and its influence on memory aging.