Janet Bryan

Verbal knowledge and speed of information processing as mediators of age differences in verbal fluency performance among older adults.

Age-related declines in verbal fluency among a large sample of older adults were investigated. Background variables, verbal knowledge, and speed of processing were examined as predictors of verbal fluency and as mediators of age effects. As expected, age-related declines were greater on the excluded letter fluency task than on the initial letter fluency task. Verbal knowledge was a better predictor of initial letter fluency than speed of processing, whereas the reverse was true for excluded letter fluency. However, speed of processing accounted for more of the age-related variance in both fluency measures than the other predictors. There was no evidence of verbal knowledge compensating for age-related declines in verbal fluency. Results suggest that verbal fluency performance is well maintained in late life and that any age-related decline appears to be mainly due to declines in speed of information processing.

Toward Understanding Age-Related Memory Loss in Late Adulthood

Background: While laboratory tests indicate that older adults typically perform more poorly than do younger adults on many types of memory tasks, the question arises as to whether, or to what extent, it is valid to attribute these differences to ageing per se or to some variable or class of variables that intervene between age and remembering. Objective: The purpose of this review is to present three current views that might explain the relationship between age and remembering. They can be construed as variants on resource theories and include: the processing speed hypothesis, the executive function hypothesis, and the common cause hypothesis. Methods: The review samples results pertinent to these hypotheses that derive from behavioural research. Studies involving various imaging techniques were considered beyond the scope of the review. Results: The balance of research strongly implicates reductions in the speed of information processing as a fundamental contributor to normal age-related memory loss. Nonetheless there are circumstances where other mechanisms, such as working memory, executive function, and sensory processes, are important. Conclusion: Despite the phenomenological and empirical reality of age-related memory loss and the breadth of attempts to explain it, much work remains to be done to understand why it occurs. Contemporary debates about the nature and means of identifying shared and unique effects promise to shape future directions for research on memory aging.

Predicting episodic memory performance of very old men and women : Contributions from age, depression, activity, cognitive ability, and speed

Regression models were developed to explain age-related and total variance in memory and to determine the independent contribution from general processing speed, having taken into account cognitive and noncognitive individual differences. Episodic memory was assessed for 3 tasks in a population-based sample of 951 adults comprising 515 men and 436 women (aged 70-96, M = 77.6, SD = 5.5). Correlations between age and memory accounted for 6%-9% of the variance. Hierarchical multiple regressions showed a reduction in this age-related variance by up to 94%, after entering gender, depression, health, cognitive status, activities, and speed. General processing speed was the major mediator of age-related variance in memory. Although both the age-related variance and the speed-related variance in memory were significantly reduced by prior entry of other individual differences variables for all 3 tasks, speed remained a significant mediator of remembering, and negligible differences in the residual age-related variance were observed by inclusion of other background variables.

The effect of weight-loss dieting on cognitive performance and psychological well-being in overweight women.

This study investigated the effect of a weight reduction diet on cognitive performance and psychological well-being among overweight women. A total of 42 women undertook a 12-week weight reduction diet while 21 women maintained their usual diet and exercise habits for 12 weeks. All women completed neuropsychologcial tests of speed of information processing, executive function, working memory, immediate and delayed recall and recognition, and verbal ability. They also completed measures of weight locus of control, dieting beliefs, self-esteem, mood and dysfunctional attitudes, before and after the 12-week interval. Being on the diet had a minimal impact on cognitive performance and a positive effect on emotional eating, feelings of depression and dysfunctional attitudes. A sense of control over weight and eating behaviour increased among the dieters, but an internal locus of control was negatively related to self-esteem.

The effect of self-initiated weight-loss dieting on working memory: the role of preoccupying cognitions

This study investigated the effects of weight loss dieting on the components of working memory and the extent to which these effects were mediated by preoccupying cognitions concerning food, diet and body shape. A dual task paradigm was used in which dieters (n=20) and non-dieters (n=20) completed mental arithmetic problems concurrently with suppression tasks designed to engage the central executive, phonological loop, and visuo-spatial sketchpad components of working memory. In addition, tasks reflecting the articulatory control process and phonological store sub-components of the phonological loop were also completed. Results showed that dieters performed more poorly on measures of the central executive and the phonological loop compared with non-dieters. Dieters reported higher levels of preoccupying cognitions which mediated the relationship between dieting status and functioning of the central executive and phonological loop, and the phonological store in particular.

Measures of fluency as predictors of incidental memory among older adults.

This study investigated fluency performance as a mediator of age-related declines in incidental memory performance as both are thought to rely on strategic retrieval processes. A large sample of community dwelling older adults completed a battery of tests assessing fluency, verbal knowledge, speed of information processing, and incidental recall. Fluency measures included initial and excluded letter fluency and the Uses for Objects Test, and they were assumed to reflect increasing reliance on strategic retrieval search. Speed emerged as the best mediator of age-related variance in incidental recall, and Uses for Objects Test performance added to the variance after controlling for verbal knowledge and speed. The results suggest that age-related decline in incidental recall is largely due to speed and the strategic search of memory.

Symptom experience in Australian men and women in midlife

OBJECTIVEnTo compare the experience of vasomotor, psychological and somatic symptoms in Australian men and women in midlife, to investigate whether symptoms often attributed to endocrine changes in midlife are associated with health and psychological well-being, and to evaluate their relationship to menopausal status in women.nnnMETHODSnA cross-sectional, correlational, population-based study based on self-report questionnaires. Participants comprised 451 men and 766 women, aged between 39 and 65, from urban and rural South Australia, who responded to invitations to participate, or who volunteered to participate following media releases. Outcome measures used comprised a 47-item symptom checklist of current presence and severity of vasomotor, somatic and psychological symptoms experienced by men and women during midlife, and measures of health and psychological well-being.nnnRESULTSnThe majority of men and women reported that they were not bothered by vasomotor, psychological and somatic symptoms. For those symptoms in which men and women differed significantly, women generally reported being more bothered than men, although the pattern of association between symptoms and measures of health and psychological well-being was the same for both men and women. Items from all three symptom clusters were independently related to menopausal status.nnnCONCLUSIONSnHealth and psychological well-being play a role in the genesis of symptoms experienced by men and women in midlife. Both men and women experience similar symptoms, although women are more distressed by them signifying support for a menopausal syndrome in women. The finding of an independent relationship between menopausal status and psychological and somatic symptoms, in addition to the vasomotor symptoms, contradicts the narrow-estrogen hypothesis of climacteric symptoms.

The manipulation and measurement of task-specific memory self-efficacy in younger and older adults

Task-specific memory self-efficacy (TSMSE) was experimentally manipulated through provision of information about task difficulty, to determine its effect on free recall for 56 older (age 63-86) and 56 younger (age 16-25) adults. The implications of using prediction-based measures of TSMSE were addressed. After completing one recall trial of a list of 20 words, half the participants were told a second list comprised more difficult words; the others were told the second list would be similar to the first they had received. Free recall and TSMSE were measured before and after this manipulation. The manipulation reduced TSMSE for participants expecting a harder list of words, but not differently for younger compared with older adults. Younger and older adults’ recall declined at the second recall trial, but there was no difference between those expecting a harder list and those expecting a similar list. Recall was predicted by domain-specific memory self-efficacy as well as a traditional measure of TSMSE. The study demonstrated the malleability of memory self-efficacy, but called into question assertions about its salience as a mediator of older adults’ poorer memory performance.

Challenges to Understanding Age-Related Memory Loss in Late Adulthood: An Introduction

Background: In the first 1999 issue of Gerontology several current hypotheses of age-related memory loss were canvassed. Objective: In hopes of fostering debate and further consideration of factors implicated in memory loss in late adulthood, commentaries were sought from a number of prominent cognitive ageing researchers on this review. Methods: Four commentaries were received and are briefly distilled in this preamble to them. Results: The papers elaborate on several themes raised in the original review, articulate assumptions implicit in the review, question the techniques used to assess mediational hypotheses, and suggest factors omitted from the review that need also to be considered. Conclusion: Despite an extensive literature on memory ageing, we are still a long way from understanding the mechanisms responsible for it. While considerable progress has already been made, over-reliance on between-person analyses, ambiguity in underlying constructs, and omission from consideration of key situation-specific characteristics of a memory episode may all contribute to a less than definitive understanding of memory ageing.

Speed of information processing and working memory as mediators of age differences in prose recall

Abstract This research investigated adult age differences in recall of a narrative text after younger and older adults engaged in the same, low-effort encoding strategy. Task-specific and task-independent measures of speed of information processing and a measure of working memory capacity were examined as potential mediators of age differences in prose memory. The effect of recall mode (oral vs. written) on prose recall was also investigated. Thirty-six younger adults (mean age = 21 years) and 36 older adults (mean age = 72 years) participated. They were required to read a story aloud once and then provide either oral or written recall of the text. Speed of processing was assessed by scores on reading time, articulation speed, and the Digit Symbol Substitution Test (DSST; Wechsler, 1981). Working memory capacity was assessed by a backward word-span measure. As expected, younger adults recalled more propositions from the text than did older adults, but there was no effect of recall mode on prose recall. Yo...