If not designed in consideration to the workings of the human mind, multimedia learning environments can impose too high a demand on working memory. While such high cognitive load presents challenges for learners of all ages, older learners may be particularly affected as research on cognitive aging has shown the efficiency of working memory declines with age. Research has suggested that cognitive load theory (CLT) and the cognitive theory of multimedia learning (CTML) are likely to accommodate the cognitive needs of older learners; however, few of the principles emerging from these theories have been examined in the context of cognitive aging. The abundance of studies has focused on younger learners, prompting the need for further research of CLT and CTML principles with regard to age. This study contributes to the body of research on the cognitive aging principle by extending research on the modality effect with middle-aged learners. Ninety-two participants ranging in age from 30 to 59 were exposed to multimedia learning treatments presented as animation with concurrent narration and animation with concurrent text, followed by retention, concept, and transfer tests of multimedia learning. Demographic and descriptive statistics were performed along with a multivariate analysis of variance. The findings did not show a modality effect with middle-aged learners; however, results need to be interpreted with care as possible explanations may entail other causes for the lack of a modality effect other than age.

This thesis project had the overall aim of investigating older adults (OA) representation of real-world objects through different cognitive paradigms probing visual working memory (vWM) and attention. OAs are known to demonstrate difficulties in these two cognitive domains, however, an under-researched in the aging field is the possible influence of the quality of representations in conjunction with the amount of representations in determining OA’s performances. Moreover, a majority of research in the aging field has utilized geometrical shapes, therefore I was interested to investigate whether the previous findings extend when real-world objects are used. Accordingly, the main questions accordingly probed in this study were 1) whether the content of object representations influence OAs’ performances when vWM and attention are probed, or whether effects are solely due to the amount, and 2) whether age-effects found in previous vWM and attention studies in aging, extend when real-world objects are used. To this aim, Chapter 3 describes two experiments where I manipulated the perceptual and conceptual similarity amongst objects presented to OAs and young adults (YAs) when performing a change detection task taxing vWM. Results indicated both age groups had significantly lower performances when there 3 objects to retain and recall, but no age-related differences in the maintenance and recall of these types of objects. Chapter 4 and Chapter 5 report three experiments addressing the impact of object numerosity and/or nature in OAs’ attention deployment during a visual search task. Results of two experiments in Chapter 4 with manual responses found that OAs’ performance was detrimentally impacted by the amount of object representations, irrespective of the relation amongst the items. Chapter 5 illustrates an eye movement study, aimed at exploring more in detail the visual exploratory behavior of older and young individuals. Overall, OAs were slower and showed a larger tendency to get distracted than YAs, regardless of the perceptual or conceptual target-distractor similarity. Overall, the studies presented in this thesis indicated that aging negatively affects the ability to ignore distracting information. However, little evidence was provided as to whether aging negatively influences the content representation of an object. This result confirms previous research indicating that some, but not all aspects, decline in late adulthood.

Cognitive control allows us to function in a world filled with constant stimulation. For example, the act of reading a book requires the ability to inhibit irrelevant information while focusing attention towards the letters on the page. Our cognitive control system regulates what information receives attention and what is denied resources. The goal of the current paper is to investigate the mechanisms underlying the activation and maintenance of the control system and how this process changes in healthy aging. First, the ability of younger and older adults to activate and maintain control in response to trial type manipulations is investigated. Second, improvements are made to recent experimental evidence suggesting younger adults are able to modulate performance based on specific stimulus history. Third, this work is extended to an older population suggesting the ability to modulate performance based on specific stimulus history is maintained in healthy aging. Finally, it is demonstrated that current theories of control fail to account for age-related differences in performance based on the comparison of trial type and specific stimulus manipulations.

Age-related inhibitory effects were investigated during spatial memory performance. In Experiment 1, 15 young (M = 20 years) and 16 old adults (M = 70 years) completed two spatial tasks (i.e., Block Suppression Test, Corsi Block Tapping Test) that differed in need for inhibitory processing. Accuracy differences within each task revealed age-related differences in spatial working memory and between task differences revealed that older adults had difficulty ignoring irrelevant items. Experiment 2 (10 young, 10 old adults) examined whether the distractibility of irrelevant items in the inhibition task (i.e. BST) accounted for the age-related inhibitory effects. Findings were largely consistent with the initial experiment indicating that inhibitory function was affected by adult aging.

The present research sought to describe and explain age related changes to associative learning processes. Eleven experiments were conducted using a human conditional learning paradigm. Background data on health, lifestyle, and cognitive ability were collected and used as predictor variables in multiple regression analyses. Experiments 1 to 8 were formative, and found that older participants showed an overall age related decline in learning ability exacerbated by the number of stimuli and outcomes used, and the concurrent presentation of different problem types. Configural models of learning (e.g. Pearce, 1994, 2002) best predicted young participants’ learning whereas older people’s learning was more consistent with elemental models (e.g. Rescorla-Wagner, 1972), suggesting an age related change in generalisation processes. Those who learned problems better were also more likely to be able to articulate a rule that had helped them learn the problem. Age itself was the most predominant predictor of accuracy in these experiments. Experiments 9, 10, and 11 were multiple stage experiments that looked at the extent of pro- and retro-active interference in learning. Experiments 9 and 10 used easy and hard HCL problems to examine the role of rule induction in learning. Older participants who had learned initial discriminations better were more prone to pro-active interference in both experiments, the extent of which was predicted most reliably by fluid intelligence. Rule learning had a profound effect on participants’ predictions during the unreinforced test stage. In Experiment 9 (Easy-Hard) younger participants suffered from more retroactive interference than older people. This pattern was far less pronounced in Experiment 10, (Hard-Easy) suggesting that problem order affected the way participants generalised from rule-based knowledge. This observation is inexplicable by associative learning theories, and explanation may require a problem solving approach. Experiment 11 examined feature-based generalisation. Again older participants suffered more proactive and retroactive interference and elemental theories predicted their responses best, whereas younger participants responses were consistent with configural models of learning. In this instance, resistance to pro- and retro-active interference was predicted by fluid intelligence. Overall the research concluded that there is a demonstrable, complexity dependent change in associative learning processes in later life. It appears that humans have an increasing tendency to rely on elemental, rather than configural processes of generalisation in later life, and this leads to overgeneralisation between stimuli and an inability to resist pro- and retroactive interference in learning. This may be as a result of an inhibitory or source monitoring failure as a consequence of atrophy in the frontal lobes of the brain, although some of the learning deficits are explicable through mnemonic decline.

abstract: Identifying modifiable causes of chronic disease is essential to prepare for the needs of an aging population. Cognitive decline is a precursor to the development of Alzheimer's and other dementing diseases, representing some of the most prevalent and least understood sources of morbidity and mortality associated with aging. To contribute to the literature on cognitive aging, this work focuses on the role of vascular and physical health in the development of cognitive trajectories while accounting for the socioeconomic context where health disparities are developed. The Assets and Health Dynamics among the Oldest-Old study provided a nationally-representative sample of non-institutionalized adults age 65 and over in 1998, with biennial follow-up continuing until 2008. Latent growth models with adjustment for non-random missing data were used to assess vascular, physical, and social predictors of cognitive change. A core aim of this project was examining socioeconomic and racial/ethnic variation in vascular predictors of cognitive trajectories. Results indicated that diabetes and heart problems were directly related to an increased rate of memory decline in whites, where these risk factors were only associated with baseline word-recall for blacks when conditioned on gender and household assets. These results support the vascular hypotheses of cognitive aging and attest to the significance of socioeconomic and racial/ethnic variation in vascular influences on cognitive health. The second substantive portion of this dissertation used parallel process latent growth models to examine the co-development of cognitive and functional health. Initial word-recall scores were consistently associated with later functional limitations, but baseline functional limitations were not consistently associated with later word-recall scores. Gender and household income moderated this relationship, and indicators of lifecourse SES were better equipped to explain variation in initial cognitive and functional status than change in these measures over time. Overall, this work suggests that research examining associations between cognitive decline, chronic disease, and disability must account for the social context where individuals and their health develop. Also, these findings advocate that reducing socioeconomic and racial/ethnic disparities in cognitive health among the aging requires interventions early in the lifecourse, as disparities in cognitive trajectories were solidified prior to late old age. / Dissertation/Thesis / Ph.D. Sociology 2011

[pt] O declínio no funcionamento cognitivo e a queixa de sintomas de ansiedade são frequentes no processo de envelhecimento. Esta dissertação tem como objetivo explorar a relação entre os sintomas de ansiedade com o desempenho cognitivo de indivíduos com idade acima de 55 anos. Está dividida em dois estudos em etapas progressivas. O primeiro estudo é uma revisão sistemática e o segundo estudo é uma pesquisa exploratória com protocolo de 73 testes cognitivos e 6 escalas de ansiedade. A amostra foi composta por 26 indivíduos idade acima de 55 anos, sendo 20 mulheres (76,92 por cento) e 6 homens (23,07 por cento), com idade média de 70,96 (mais ou menos 8,42) anos e escolaridade média de 16,23 ( mais ou menos 3,68) anos de escolaridade. Calcularam-se coeficientes de correlação e, para as correlações com efeito médio ou grande, foi feita análise de regressão linear. Em seguida, repetiu-se a análise em uma subamostra, considerando-se apenas os participantes com ansiedade acima do ponto de corte em pelo menos uma escala de ansiedade. Observaram-se mais correlações com efeito de tamanho médio ou grande na análise da subamostra. Em cada análise foram observadas 11 correlações significativas com efeito de tamanho médio ou grande, apontando associação entre ansiedade e funções cognitivas. A regressão linear destas correlações apontou que o aumento do nível de ansiedade reduz o desempenho em tarefas cognitivas. Conclui-se que os resultados apontam dissociação nos diferentes sistemas de ansiedade: (1) estado de ansiedade afetando memória de trabalho; (2) traço de ansiedade afetando memória episódica e velocidade de processamento; e (3) os sintomas fisiológicos da ansiedade afetando o controle inibitório. / [en] The decline in cognitive functioning and the complaint of anxiety symptoms are frequent in the aging process. This dissertation aimed to explore the relationship between anxiety symptoms and the cognitive performance of individuals aged over 55 years. It is divided into two studies in progressive stages. The first study is a systematic review and the second study is an exploratory research with protocol of 73 cognitive tests and 6 anxiety scales. The sample consisted of 26 individuals aged over 55 years, 20 women (76.92 percent) and 6 men (23.07 percent), with a mean age of 70.96 (plus or minus 8.42) years and average schooling of 16.23 (plus or minus 3.68) years of schooling. Correlation coefficients were calculated and, for correlations with medium or large effect, linear regression analysis was performed. Thereafter, the analysis was repeated in a subsample, considering only participants with anxiety above the cutoff point on at least one anxiety scale. There were more correlations with medium or large size effect in the subsample analysis. In each analysis, 11 significant correlations were observed with medium or large size effect, indicating an association between anxiety and cognitive functions. The linear regression of these correlations pointed out that the increase of the level of anxiety reduces the performance in cognitive tasks. We conclude that the results point to dissociation in the different anxiety systems: (1) anxiety state affecting working memory; (2) anxiety trait affecting episodic memory and processing speed; and (3) the physiological symptoms of anxiety affecting the inhibitory control.

L’effet du vieillissement sur les fonctions cognitives de haut niveau demeure encore relativement incompris. Cette recherche vise à mieux comprendre les différences interindividuelles de performances entre les individus jeunes et âgés par l’étude des processus de contrôle attentionnel mis en jeu dans les tâches de commutation attentionnelle. Dans unpremier temps, deux tâches d’alternance de type séries alternées ont été administrées à des adultes jeunes et âgés. Les résultats n’indiquent pas d’effet de l’âge sur les coûts d’alternance mesurés mais en revanche un coût d’alternance symétrique (étude 1) et des coûts d’alternance locaux et globaux différents selon les individus (étude 1 et 2). Dans un second temps, un travail de modélisation du fonctionnement cognitif à l’aide de l’architecture cognitive ACT-R a été réalisé. Il permet de tester la plausibilité des hypothèses de diminution de la vitesse de traitement (VT) et de diminution de la capacité de la mémoire de travail (CMT), à pouvoir reproduire les différences de performances entre jeunes et âgés. Lesrésultats des tests d’hypothèse pour les deux études réalisées indiquent que ces hypothèses ne reproduisent pas assez les effets empiriquement observés ce qui suppose que les hypothèses de diminution de la VT ou de la CMT sont insuffisantes pour expliquer les différences de performances individuelles observées. Cette étude met en évidence l’intérêt de la modélisation cognitive computationnelle dans la compréhension des processus sous-jacent le fonctionnement cognitif humain / The effect of aging on high level cognitive functions is still relatively misunderstood. The aim of this research is to better understand individual performance differences between young and elderly individuals, by studying the attentional control processes involved in task switching. Initially, two switching tasks were administered to young and elderly adults. The results indicate no age effect on the switching cost but show an asymmetric switching cost (Study 1) and differentlocal and global switching costs between individuals (study 1 and 2). In a second step, a computational cognitive modeling of cognitive functioning is built using the ACT-R architecture. It enables to test the veracity of the assumptions of reduced processing speed (VT) and reduced capacity of working memory (WCL), to reproduce the observed performance differences between young and old individuals. The results of the hypothesis tests for both studies indicate that these assumptions do not reproduce adequately the empirically observed effects, which implies that the assumptions of decreased VT or CMT are insufficient to explain the individual performance differences observed. This study highlights the interest of computational cognitive modeling in the understanding of the processes underlying human cognitive functioning

Objective: The transition to long-term care (LTC) of older adults receiving home care services is preceded by declining functional independence with basic and instrumental activities of daily living (ADL and IADL, respectively). These individual, and group, level time-dependent changes occur within unique provincial and regional policy contexts across Canada, which determine the amount and types of services received by home care recipients during this transition period. It is currently unknown whether activities of daily living (ADL) or IADL (instrumental activities of daily living) exhibit accelerated decline preceding transition to LTC, and if so, whether the onset and rate of decline differs for ADL versus IADL. This dissertation sets out to determine whether such change points exist within longitudinal data gathered from home care recipients in Ontario during the years of 2008 to 2015. Methods: A profile likelihood method was employed to identify the best fitting change points at which the slopes of functional decline in ADL and IADL for those who transition to LTC from home care services depart from the normative age slope of those who remain in community. Data analyzed was collected at approximately 6-month intervals using the International Residential Assessment Instrument – Home Care (RAI-HC) in Ontario, Canada, and was obtained from the Canadian Institutes for Health Information (CIHI) for the period of 2006-2015. A policy review was conducted to determine whether changes had occurred to the amount or type of home care services provided during the data collection period, and subsequently data from 2008 to 2015 were retained. IADL was measured using the 21-point IADL Involvement Scale and ADL was measured using the 28-point ADL Long Form. Best fitting change point models were first identified for ADL and IADL scores in the full sample of participants who remained in community and those who transitioned to LTC and within subgroups stratified by sex. Two additional subgroups were also examined: 1) participants without a primary or secondary caregiver living in the home, and 2) participants with a primary caregiver living in the home. Each caregiver group was also stratified by sex, resulting in a total of 9 groups in which IADL and ADL change points were estimated and compared. Results: In all groups who remained in community with home care services, age-related decline in IADL and ADL were observed. Further, IADL impairment was higher at the time of first assessment and had a greater age-related slope than ADL for those who remained in community. Both measures had discernable change points preceding discharge to LTC and the change point for IADL preceded that of ADL in all groups. Across groups, the change point for ADL had a range of 0.5 years before LTC discharge for men without a primary or secondary caregiver living in the home to 2 years for women with a primary caregiver in the home. IADL change points ranged from 2.5 years before LTC discharge for men with a primary caregiver in the home to 3.6 years for women without a primary or secondary caregiver in the home. Within the full sample, including both men and women, the onset of accelerated IADL decline for those discharged to LTC preceded the onset of home care service by 1.49 years and the time of first assessment by 1.84 years. Women in the full sample, and in both caregiver groups, experienced an earlier IADL change point relative to the availability of home care services and assessment when compared to men. Conclusions: Both IADL and ADL have discernible change points for in the years preceding discharge from home care to LTC. The change point for IADL consistently precedes that of ADL for the entire sample, for those with or without a caregiver in the home and for both men and women. The onset of accelerated IADL decline in the presence of age normative ADL decline may be an early indicator of pending transition from home care to LTC for home care recipients identified in this study. The province of Ontario has committed to providing the right care, at the right time in the right place. This study demonstrates that home care policy in Ontario during this study period, which does not provide for IADL services until after patients first qualify for ADL services, may not be achieving the provinces commitment of ensuring IADL care is provided at the right time for recipients of home care services. Opportunities for early identification and intervention may be available through early monitoring of, and intervention with, IADL function. A stepped care model holds promise for early identification and intervention of IADL impairment in community living older adults. Future research will help to confirm if accelerating decline in IADL function in the absence of appropriate rehabilitation and support services may hasten the onset of accelerated ADL impairment and subsequent admission to LTC. / Graduate / 2022-12-16

La perception pour un individu que son fonctionnement est déterminé par ses propres actions et comportements serait l’un des facteurs clés d’un vieillissement cognitif réussi. Cette perception de contrôle conduirait à fournir des efforts soutenus pour rester performant sur le plan cognitif en dépit de l'avancée en âge, ce qui contribuerait au maintien de bonnes habiletés cognitives au fil du temps. Aujourd’hui, de nombreux travaux mettent en évidence que les personnes avec un fort sentiment de contrôle obtiennent de meilleures performances dans les tâches de mémoire épisodique que les autres. Néanmoins, l’hypothèse d’une préservation différentielle des capacités de mémoire épisodique en fonction du niveau de contrôle perçu manque encore de soutien empirique. A travers trois études expérimentales et la validation d’une nouvelle échelle de contrôle perçu spécifique à la mémoire, la présente thèse visait à déterminer si le contrôle perçu pouvait jouer un rôle positif dans l’évolution de la mémoire épisodique au fil de l’âge adulte puis à identifier les mécanismes explicatifs de la relation entre le contrôle perçu et la mémoire épisodique à différents âges de la vie adulte. Dans l’ensemble, nos études ne permettent pas de valider l’hypothèse selon laquelle un contrôle perçu plus élevé atténuerait les différences liées à l’âge en mémoire épisodique. En revanche, nos résultats suggèrent que les personnes, et en particulier les plus âgées, qui perçoivent leur mémoire comme contrôlable obtiennent de meilleures performances de mémoire épisodique que les autres grâce à une plus grande utilisation et à une exécution plus efficace de stratégies cognitives coûteuses en termes de ressources au cours de la tâche. / Perceiving one’s own functioning as determined by one’s own actions and behaviors would be one of the key factors of successful cognitive aging. Perceived control would lead to sustained efforts to maintain a high level of cognitive performance despite advancing age, which would predict a positive evolution of cognitive abilities over time. Currently, many studies show that people with higher levels of sense of control have better memory performance than people who believe that events are beyond their control. Nevertheless, there is still a lack of empirical support concerning the hypothesis of a differential preservation of memory abilities as a function of levels of perceived control. Through three experimental studies and the validation of a new scale evaluating memory control beliefs, this thesis aimed to determine whether perceived control could make a positive contribution to memory aging and to identify the mechanisms that may explain the relationship between perceived control and episodic memory at different ages. Overall, our studies do not support the hypothesis that higher perceived control would moderate age-related differences in episodic memory. However, our work suggests that individuals, especially the older ones, who perceive their memory as controllable obtain better performance during memory tasks than those who perceive their memory as uncontrollable through greater and more efficient use of resource-demanding cognitive strategies.