Memory inhibition across the lifespan

Age can affect memory performance. This statement is so often heard that it has become almost a truism. When research surrounding memory inhibition – the ability to ignore irrelevant material to aid in the retrieval of a target memory – is examined specifically, a more mixed picture of findings emerges. Whilst some previous work has found evidence of an age-related deficit, other research has rather found intact memory inhibition in older adults. Less often discussed, too, are the effects of individual differences on memory inhibition in addition to age, including differences in metacognitive strategy, working memory capacity, stress and mood. The present thesis set out primarily to investigate the effects of age on memory inhibition chiefly using cognitive experimental paradigms, and also to investigate potential individual differences in this ability which exist across the lifespan. The findings of the present thesis showed that age alone was not related to a deficit in memory inhibition, - young and older adults rather showed equivalent levels of inhibitory forgetting on two different paradigms, when methodological measures were put in place to control for alternative, interference-based explanations (Study 1). These findings also could not be explained by differences in metacognitive, covert-cuing strategies (Study 2). Instead, age-related inhibitory deficits were qualified by differences in working memory capacity (Study 3a & b). In combination, older age and low working memory capacity were related to impaired memory inhibition, whereas young age or high working memory capacity were not. Finally, natural variations in stress and mood over time were found to be related to significant differences in working memory capacity, but not memory inhibition (Study 4). This suggests that these important cognitive abilities may be capable of changing even over relatively short time periods, and thus they may also potentially be improved, - a proposal which is considered in the General Discussion