In this thesis I explore how older people make use of, and interact with, their physical environment in home and near-by settings to manage cognitive situations, specifically prospective memory situations. Older adults have in past research been shown to perform better on prospective memory in real-life settings than what findings in laboratory-like settings predict. An explanation for this paradox is that older adults has a more developed skill of using the environment for prospective memory than younger adults. However, research investigating this explanation has primarily been based on self-reports. I contribute to the understanding of this skill by doing two related things. First I introduce distributed cognition, a theoretical perspective that primarily has been used within professional and socio-technical environments, to the research field of prospective memory in everyday life. Second I present a cognitive ethnography conducted during two years across eight home, and near-by, environments and old-age retired persons, for which I have used theoretical concepts from distributed cognition to analyze observations. The analysis shows rich variations in how participants use common cultural cognitive tools, invent their own cognitive tools, deliberately and incidentally shape more or less functional spaces, make use of other physical features, orient themselves toward and make sense of cognitive resources. I complement both prospective memory and distributed cognition research by describing both the intelligent shaping and use of space. Furthermore, by taking a distributed cognitive perspective I show that prospective memory processes in home environments involve properties, and the management, of a multipurpose environment. Altogether this supports the understanding of distributed cognition as a perspective on all cognition. Distributed cognition is not a reflection of particular work practices, instead it is a formulation of the general features of human cognition. Prospective memory in everyday life can be understood as an ability persons have. However, in this thesis I show that prospective memory can also be understood as a process that takes place between persons, arrangements of space, and tools.

Introduction: The prefrontal cortex (PFC) is highly susceptible to age-related deterioration. As such, executive function deficits are commonly observed when older adults process two attention-demanding tasks simultaneously. Everyday tasks such as walking and talking on the phone involve executive functions and the integration of cognitive-motor pathways. However, less is known about this relationship as cognitive demands increase. Methods: Twenty healthy older adults (M = 71.8 years, SD = 6.4) performed four auditory cognitive tasks of increasing demand, including a simple reaction time (SRT), go/no-go (GNG), n-back (NBK), and double number sequence (DNS) task with or without self-paced walking (i.e., single- versus dual-task). Using a blocked design, prefrontal hemodynamic changes (i.e., oxy- [∆HbO2] and deoxyhemoglobin [∆HbR]) were measured using functional near-infrared spectroscopy (fNIRS) and performance was assessed using measures of response time (s), accuracy (% correct) and gait speed (m/s). Results: Prefrontal activation decreased between the single- and dual-tasks across all task demands. Behaviourally, the SRT response times were significantly faster than GNG and NBK. Accuracy decreased between single- and dual-tasks and with increasing demand, but the NBK and DNS tasks were not significantly different. An interaction between task and demand was observed for gait speed such that the DNS dual-task was significantly slower than the single-task. Conclusion: Neural findings support an automatic locomotor control strategy in that cerebral oxygenation decreased between single- and dual-tasks and gait speed was maintained up until the most demanding cognitive task. However, decreased prefrontal activation was inefficient at supporting response time and accuracy performance which may indicate that cognitive performance is differentially affected by cognitive demand and deficits in executive functioning.

Metamemory is “knowing about knowing” (Flavell, 1971) and is theorized as a cognitive process that monitors and controls the memory system (Flavell & Wellman, 1975; Nelson & Narens, 1990). The predominate finding in the metamemory and aging literature is that metamemory is unimpaired by aging, even when memory is impaired by aging (Eakin & Hertzog, 2006; 2012; Connor, Hertzog, & Dunlosky, 1997; Hertzog, Sinclair, & Dunlosky, 2010; Eakin, Hertzog, & Harris, 2014, but see Souchay, Moulin, Clarys, Taconnat, & Isingrini, 2007). However, a study examining metamemory for emotional words suggests older adults may show metamemory impairment when predicting memory for emotional words (Tauber & Dunlosky, 2012). This finding challenges the supposition that metamemory is unimpaired with aging. The purpose of the current study was to expand on the results from Tauber and Dunlosky (2012) to determine whether their findings were due to methodological issues rather than age-related deficits in metamemory.

Older adults' ability to make accurate metamemory judgments indicates that aging spares metamemory (Eakin & Hertzog, 2006; 2012a; but see Souchay et al., 2006). However, age differences in metamemory accuracy for emotional information, particularly lists of positive and neutral words, indicate potential age-related impairment of metamemory (Tauber & Dunlosky, 2012; Flurry & Eakin, manuscript in preparation). These age differences may be explained by potential cue overshadowing effects (Price & Yates, 1993) in which older adults primarily used the salient cue, emotional valence, and overlooked additional cues that were diagnostic of memory. We hypothesized that age differences in metamemory for emotional words may be eliminated when older adults have a second salient and diagnostic cue to inform judgments of learning (JOLs). We manipulated multiple cues, emotional valence and endorsement (Craik & Tulving, 1975), using a category inclusion task in which participants responded "yes" or "no" to endorse positive words (e.g. "champion") or neutral words (e.g. "sphere") as category members (e.g. "is an achievement"). Age comparisons in free recall and JOL magnitude between levels of emotional valence (positive, neutral) and levels of endorsement (yes, no) indicate that both younger and older adults' JOL magnitudes responded to emotional valence and endorsement effects in which memory was higher for positive than neutral words, and "yes" versus "no" words. JOL accuracy results demonstrate that both age groups' JOLs were significantly accurate above chance within each level of valence and endorsement. Age comparisons in JOL accuracy suggest that including a second salient cue eliminated previously reported age differences in metamemory for positive and neutral words. These results demonstrate that older adults can use multiple cues to make accurate JOLs in the presence of a salient cue. This finding supports a conclusion that previously reported age differences in metamemory for emotional words can be attributed to cue overshadowing effects that diminished older adults' ability to use multiple cues. This conclusion has implications on the aging and metamemory literature such that additional age differences reported in episodic metamemory may also be attributed to conditions that hindered multiple cue use by older adults.

Résumé : La psychologie cognitive s'intéresse depuis quelques années à un effet de positivité qui semble apparaître avec l'avancement en âge. Cet effet serait également lié à la diminution, voire la disparition, d'un biais attentionnel négatif, naturellement présent chez les jeunes adultes. Celui-ci consiste en une plus grande perturbation de l'attention sélective en présence de stimuli négatifs. Une tâche cognitive d'attention sélective très utilisée pour étudier ce biais cognitif est le Stroop émotion. Présentant des mots à valence négative, positive et neutre, il permet de vérifier l'effet d'interférence que produisent ces stimuli sur la capacité d'inhibition. Jusqu'à présent, les rares études utilisant le Stroop émotion auprès d'une population âgée sans trouble cognitif ne présentent pas de consensus permettant de statuer clairement sur la modification de ce biais cognitif dans le vieillissement. La présente étude proposait d'utiliser le Stroop émotion pour observer l'effet du vieillissement sur l'attention sélective, en répondant aux principales recommandations méthodologiques tirées des études précédentes. Il était attendu que les âgés ne devaient pas présenter d'effet d'interférence en réponse aux stimuli négatifs, contrairement aux jeunes adultes. Les résultats obtenus ont toutefois révélé la présence d'un biais attentionnel négatif tant chez les âgés que chez les jeunes adultes. L'interprétation de ces performances est discutée en regard des exigences cognitives du Stroop émotion. Il pourrait ainsi être plus facile de mettre en évidence la diminution du biais attentionnel négatif à l'aide d'une présentation différente des stimuli qui permettrait la mise en place de l'effet de positivité chez les âgés.||Abstract : For some years now, cognitive psychology has taken an interest in a positivity effect that appears with increased age. This effect is claimed to be related to the decrease in, or even disappearance of, a negative attentional bias that is naturally present in young adults; this effect consists in a greater disruption of selective attention in the presence of negative stimuli. A cognitive task measuring selective attention that is often used to study this cognitive bias is the emotional Stroop test. This task presents words with negative, positive and neutral valence and tests how these stimuli interfere with inhibition capacity. To date, the few studies that have used the emotional Stroop in an elderly population without cognitive disorders have not produced a consensus that would give us a clear sense of the change in this cognitive bias with aging. This study proposed to use the emotional Stroop to observe the effect of aging on selective attention by following the main methodological recommendations arising from earlier studies. It was expected that elderly people would not present an interference effect in response to negative stimuli, unlike young adults. However, the results revealed a negative attentional bias in both older and younger adults. This finding is interpreted in relation to the cognitive demands of the emotional Stroop. It could therefore be easier to highlight the decrease in negative attentional bias by using a different method of presenting stimuli, which would reveal the positivity effect in elderly people.

The ability to make associations between causal cues and outcomes is an important adaptive trait that allows us to properly prepare for an upcoming event. Encoding context is a type of associative processing; thus, context is also an important aspect of acquiring causal relationships. Context gives us additional information about how two events are related and allows us to be flexible in how we respond to causal cues. Research indicates that older adults exhibit an associative deficit as well as a deficit in contextual processing; therefore, it seems likely that these deficits are responsible for the deficit in older adults’ causal learning. The purpose of the current study was to more directly test how associative deficits related to older adults’ contextual processing affect their causal learning. Based on past research, it was hypothesized that older adults would be less likely than younger adults to acquire and use contextual information in causal learning. A causal learning scenario from Boddez, Baeyens, Hermans, and Beckers (2011) was used to test the hypothesis that older adults show deficits in contextual processing in a causal learning scenario. This task examined contextual processing using blocking and extinction. Participants went through eight blocks of trials in which they were exposed to various cues and outcomes. They provided expectancy ratings that indicated how likely they believed an outcome was to occur, and these ratings were used to assess age differences in use of contextual information in a causal learning scenario. As expected, both younger and older adults demonstrated blocking in that they assigned higher causal value to a previously trained target cue (A+) than to another cue (X) that was only presented in compound with cue A later in the task (i.e., AX+). Additionally, when tested in the context where the association was originally learned following extinction training (i.e., A-), the causal value of cue A decreased for all groups, even if extinction training took place in a different context. However, ratings for cue A decreased even more for younger adults whose extinction training took place in a different context when tested in their extinction context.

Cognitive impairment no dementia (CIND) is conceptualized as a stage of cognitive decline between normal aging and onset of dementia. As persons with CIND are at high risk of developing dementia, efforts to determine early predictors of cognitive decline are warranted to advance both clinical knowledge and practice. Recent evidence suggests persons with CIND may have changes in vascular function compared to non-impaired peers, which may have clinical potential to differentiate those with and without CIND. The purpose of this study is to determine whether vascular functioning, examined both by individual indicators and as an aggregate vascular factor, will be associated with cognitive impairment. It is expected that the individual vascular indicators of hypertension, diabetes, stroke, and heart problems will be related to cognitive status classification, with poorer vascular function being more strongly associated with CIND as compared to the control group. Further, it is expected that examining the aggregate vascular factor in a multivariate approach will be more strongly associated with cognitive status than examining the vascular indicators individually. Data for this study were collected in the Victoria Longitudinal Study (VLS), a large-scale longitudinal, sequential study of community-dwelling older adults in Victoria, British Columbia. Cognitive group status was determined by a distributional approach based on scores on 5 cognitive reference measures. The associations between all vascular factors and cognitive status groups were assessed using chi-square analyses. Univariate analyses were then carried out using ordinal logistic analysis. A multivariate approach using discriminant analysis was then used to determine if cognitive status group membership was associated with vascular function based on linear combinations of vascular indicators. Contrary to expected results, we did not find a significant association between any of the vascular indicators (i.e., blood pressure classification, severity of stroke, severity of heart troubles, and severity of diabetes) and the cognitive status classifications. Further, group membership was not associated with any of the individual vascular markers, or by a multivariate combination of the indicators. Several reasons for this study’s findings include discrepant definitions of cognitive impairment in the literature, sample characteristics (i.e. high education, low base rate of vascular problems), and methodological considerations. Future research objectives should address the longitudinal association of vascular function and cognitive status. / Graduate

Objective: This dissertation was undertaken to explore the clinical utility of physiological and behavioural metrics of neurocognitive adaptability in the screening of older adults for possible early signs of pathological cognitive aging. Methods: This was an intensive, multi-method study of 44 healthy (non-demented) Victoria-area older adults (ages 65 to 80 years). Study 1 examined timescale-specific differences in resting electroencephalographic (EEG) adaptability as a function of subtle cognitive decline. Study 2 described differences in retest practice effect -- within and across a burst of 4 to 6 occasions of computerized cognitive testing -- with respect to individual variation in estimated premorbid function and self-reported conscientiousness. Study 3 considered whether practice effects from Study 2 were related to individual differences in the resting EEG marker derived in Study 1, above and beyond the differences due to premorbid function and conscientiousness. Results: Study 1 revealed that older adults with neuropsychological performance indicators of subtle cognitive decline also showed subtle, timescale-specific differences in resting EEG adaptability. Study 2 illustrated the differentiable effects of individual differences in estimated premorbid function and conscientiousness on within- and across-occasion improvement on a computerized attention-shifting (switch) task. Study 3 demonstrated the unique promotional effects exerted by conscientiousness and resting EEG adaptability on the rate of across-occasion improvement in cognitive performance. Conclusions: Useful yet under-used tools for detecting early signs of neurocognitive decline include rigorous, standardized neuropsychological diagnostic criteria, the magnitude of practice-related improvement in cognitive performance, and characteristics of the brain's resting electrical activity. Future multi-method, ecologically-situated studies are needed to establish standardized protocol that can be used to screen growing worldwide numbers of older adults for losses in neurocognitive adaptability that may herald the earliest stages of pathological neurocognitive aging. / Graduate

Purpose of review: This article critically reviews the utility of “phenotypes” as behavioral descriptors in aging/HIV research that inform biological underpinnings and treatment development. We adopt a phenotypic redefinition of aging conceptualized within a broader context of HIV infection and of aging. Phenotypes are defined as dimensions of behavior, closely related to fundamental mechanisms, and, thus, may be more informative than chronological age. Primary emphasis in this review is given to comorbid aging and cognitive aging, though other phenotypes (i.e., disability, frailty, accelerated aging, successful aging) are also discussed in relation to comorbid aging and cognitive aging. Recent findings: The main findings that emerged from this review are as follows: (1) the phenotypes, comorbid aging and cognitive aging, are distinct from each other, yet overlapping; (2) associative relationships are the rule in HIV for comorbid and cognitive aging phenotypes; and (3) HIV behavioral interventions for both comorbid aging and cognitive aging have been limited. Summary: Three paths for research progress are identified for phenotype-defined aging/HIV research (i.e., clinical and behavioral specification, biological mechanisms, intervention targets), and some important research questions are suggested within each of these research paths.

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