Everyday Memory Failures and Strategy Use in Healthy Adults across the Lifespan: a Mixed Methods Approach

Abstract

For several decades, research on cognitive ageing has been using primarily laboratory methods of investigation. However, recent advances in cognitive psychology and related areas have started to emphasise the importance of supplementing laboratory studies with other empirical methods such as experience sampling and diary methods. The development of new tools and combined methodology is necessary for further advancing the understanding of how ageing mind operates both inside and outside the laboratory. For example, results from laboratory research in memory and ageing consistently show fairly large negative age effects, and it is assumed that similar impairments in older adults’ memory functioning would be observed in everyday life. However, there is very little research on memory functioning of young and older adults in everyday contexts and several naturalistic studies on participants’ ability to remember to carry out simple tasks (e.g., making a phone call) have resulted in the so called age-prospective memory paradox, showing that while younger adults significantly outperform old in the laboratory, older adults often outperform young on remembering to do things in everyday life. Moreover, these counterintuitive findings have been further confirmed by a couple of recent diary studies, which showed that older adults recorded fewer prospective memory failures than younger adults, but no age differences were found in the number of recorded retrospective failures (forgetting past information, for example, people’s names, event details, etc.) or more attentionally based absent-minded failures (doing one thing instead another, not completing an action due to distraction, etc.). These initial diary studies cast further doubts on the assumption that laboratory findings will automatically generalise to how memory operates in everyday life and call for more targeted investigation of age-related changes, stability or even benefits in everyday contexts. Unfortunately, the results from a limited number of structured diary studies of everyday memory failures are often met with scepticism and pessimistic suggestions that the absence of age effects or positive age effects are possibly obtained because of older adults’ impaired ability to remember to record what they forget, or their increased use of memory strategies, which may result in them having fewer recorded failures in diaries. Similar explanations are often provided whenever no age effects are obtained in self-reported questionnaire studies of everyday memory. Based on these explanations and initial results from diary studies of everyday memory failures, the principal aim of the present thesis was to carry out a first systematic investigation of everyday memory failures and strategy use across the lifespan of healthy adults using a structured diary method and the newly developed questionnaires assessing the frequency of memory failures and strategy use with items empirically validated from structured diary studies of memory failures (Study 1a) and memory strategy use (Study 1b). In addition, questionnaire and laboratory studies to date provide indication that there is a link between memory failures and levels of busyness, mood and procrastination, but no previous diary study has examined this question. Therefore, the second major objective of the present thesis was to investigate the relation between recorded memory failures and these individual difference variables and examine if they moderated the effects of age on the number of recorded prospective memory, retrospective memory and absent-minded failures. Considering growing evidence which shows that older adults’ performance in laboratory studies of memory can be impaired by holding negative stereotypical views on memory in old age, a final aim of this thesis was to systematically investigate the magnitude and direction of stereotypical views that people across the adult lifespan may hold towards memory and ageing. Overall, results from two diary studies of everyday memory failures suggest that not only is structured diary a reliable method for studying everyday memory failures (Study 2) but that it is able to produce replicable findings by demonstrating no age effects on the overall number of recorded memory failures (Study 1a and Study 2). These results did not change when accounting for differences in participants’ mood and the levels of busyness. In addition, diary studies provided further support for the existence of age-prospective memory benefit (Study 1a), with older adults recording fewer prospective memory failures than younger adults. However, this age benefit disappeared once the levels of procrastination were taken into the account (Study 2), indicating that the age-prospective memory paradox reported in the literature could potentially be explained by younger adults’ increased levels of procrastination rather than prospective memory forgetting per se. Importantly, the results also showed that young and older adults did not differ in the number of memory strategies that they recorded in a diary (Study 1b), a finding that was further confirmed in a newly developed questionnaire study (Study 4a). Results from two questionnaire studies also indicate that while participants self-reported strategy use reflects patterns of findings obtained in diary of strategy use (Study 1b), when responding to a questionnaire on everyday memory failures participant’s responses were very different from what was found in a diary study of everyday memory failures (Study 3a). Here, only older adults self-reports reflected with some accuracy results from a diary study, but young adults’ ratings of how often they experienced everyday memory failures were in complete contrast to what was found in diary studies (Study 1b and Study 2). Finally, the results demonstrate the existence of strong negative age stereotypes in both, judging the frequency of everyday memory failures in others (people aged 20s, 40s, 60s and 80s) and when judging the memory strategy use in these target age groups (Studies 3b and 4b). Interestingly, the stereotypes exist in both directions, with young adults thinking that all types of forgetting increase with age, and older adults thinking that young and middle-aged adults have almost perfect memory in everyday life. Taken together, the results significantly advance existing knowledge on effects of age on everyday memory functioning and provide important methodological tools to launch a more systematic investigation of factors affecting everyday memory functioning and ageing in both healthy and clinical samples (e.g., people with Mild Cognitive Impairment).