The impact of aerobic activity on cognitive function in older adults: A new synthesis based on the concept of executive control

Numerous reaction time studies have suggested that age-related declines in cognitive function might be ameliorated by lifestyles involving aerobic activity or by interventionist programmes of aerobic exercise. These studies are far from conclusive, however, reflecting a failure to factor out cognitive from sensory and motor processes. Following a critical review of the literature, we report on recent developments that differentiate cognitive processes involving executive vs non-executive control, the former being associated with frontal lobe function. Three key studies suggest that aerobic exercise primarily improves executive control.     

Neurocognitive ageing of storage and executive processes

Converging behavioural and neuropsychological evidence indicates that age-related changes in working memory contribute substantially to cognitive decline in older adults. Important questions remain about the relationship between working memory storage and executive components and how they are affected by the normal ageing process. In several studies using positron emission tomography (PET), we find age differences in the patterns of frontal activation during working memory tasks. We find that separable age differences can be linked to different cognitive operations underlying short-term information storage, and interference resolution. Some operations are associated with age-related increases in activation, with older adults displaying bilateral activations and recruiting prefrontal areas more than younger adults. Other operations are associated with age-related decreases in activation. We consider the implications of these results for understanding the working memory system and potential compensatory processes in the ageing brain.     

Spatial problem solving and functional relations

Three experiments investigated the role of object knowledge on participants' ability to solve a spatial arrangement problem. The task was to rearrange six real-world three-dimensional objects so that their relative locations agreed with a given set of rules. The aim of the experiments was to tease out the relative extent to which object association, orientation, and object-specific functional relations affect performance on arrangement tasks. When the problem was presented vertically (objects arranged in piles), participants solved functional canonical versions of the problem significantly quicker than functional non-canonical versions both between (Experiments 1a and 2), and within subjects (Experiment 3). When the arrangement problem was presented horizontally (objects arranged flat in two rows), no significant differences in solution times were found between conditions (Experiments 1b and 2). Overall the results provide evidence for the importance of object-specific functional relations as a predictor of the solution time of spatial arrangement problems, although some differences were noted between single and multiple presentation of problems when specific rules within problems were rotated. The importance of functional information in memory as a constraint on the building of mental models and problem spaces is discussed.     

Simple arithmetic processing: Individual differences in automaticity

This study investigated individual differences in the ability to automatically access simple addition and multiplication facts from memory. It employed a target-naming task and a priming procedure similar to that utilised in the single word semantic-priming paradigm. In each trial, participants were first presented with a single digit arithmetic problem (e.g., 6+8) and were then presented with a target that was either congruent (e.g., 14) or incongruent (e.g., 17) with this prime. Response times for congruent and incongruent conditions were then compared to a neutral condition (e.g., X+Y, with target 14). For the high skilled group, significant facilitation in naming congruent multiplication and addition targets was found at SOAs of 300 and 1000?ms. In contrast, for the low skilled group, facilitation in naming congruent targets was only observed at 1000?ms. Significant inhibition in naming incongruent multiplication and addition targets at 300?ms, and addition targets at 1000?ms, was found for the high skilled group alone. This advantage in access to simple facts for the high skilled group was then further supported in a problem size analysis that revealed individual differences in access to small and large problems that varied by operation. These findings support the notion that individual differences in arithmetic skill stem from automaticity in solution retrieval and additionally, that they also derive from strategic access to multiplication solutions.     

Nature over nurture: temperament, personality, and life span development

Temperaments are often regarded as biologically based psychological tendencies with intrinsic paths of development. It is argued that this definition applies to the personality traits of the five-factor model. Evidence for the endogenous nature of traits is summarized from studies of behavior genetics, parent-child relations, personality structure, animal personality, and the longitudinal stability of individual differences. New evidence for intrinsic maturation is offered from analyses of NEO Five-Factor Inventory scores for men and women age 14 and over in German, British, Spanish, Czech, and Turkish samples (N = 5,085). These data support strong conceptual links to child temperament despite modest empirical associations. The intrinsic maturation of personality is complemented by the culturally conditioned development of characteristic adaptations that express personality; interventions in human development are best addressed to these.     

Effects of mothers' locus of control for child improvement in a developmentally delayed sample

A potentially important variable that has received little attention in the literature is the locus of control (LOC) a caregiver holds for child improvement, including its influence on the caregiver's treatment compliance and on actual child improvement. In this study, 131 mother-child dyads were assessed across 1 year, to evaluate the utility of the LOC construct in a practice setting. Children were approximately 4 years old at the first assessment, and all of them had been diagnosed with a developmental disability. Mothers' compliance with treatment (mothers' attendance at sessions; teachers' ratings of mothers' support and knowledge) was tracked, and measures of child development status and mothers' locus of control were administered. Statistical results indicated that mothers' locus of control was not significantly correlated with children's gains in development over the year. The mothers' beliefs about whether the child or chance would be responsible for improvement were associated with lower compliance with treatment, whereas the mothers' beliefs that child improvement was attributable to professional intervention were associated with enhanced involvement in treatment.     

Vocational students' learning preferences: the interpretability of ipsative data

A number of researchers have argued that ipsative data are not suitable for statistical procedures designed for normative data. Others have argued that the interpretability of such analyses of ipsative data are little affected where the number of variables and the sample size are sufficiently large. The research reported here represents a factor analysis of the scores on the Canfield Learning Styles Inventory for 1,252 students in vocational education. The results of the factor analysis of these ipsative data were examined in a context of existing theory and research on vocational students and lend support to the argument that the factor analysis of ipsative data can provide sensibly interpretable results.     

Not to be and then to be: visual representation of ignored unfamiliar faces

Negative priming, the increase in response time and/or errors to targets previously encountered as distractors, is explained by inhibitory mechanisms that block the access of distractor representations to response systems. The processing of unfamiliar human faces was investigated using negative priming. Observers viewed a row of faces to decide whether 2 target faces were the same or different. Response latencies were longer when 1 or both targets had appeared as distractors on the immediately preceding trial--evidence that never-before seen faces are represented and require inhibition. Response latencies were shorter when face targets had appeared as distractors, either corrupted with high-frequency noise or contrast inverted--evidence that representations are facilitated. Finally, response latencies remained unaltered when face targets had appeared as upside-down distractors--evidence that not all distractor representations afford response priming. The visual system indeed represents ignored unfamiliar faces, but blocks these representations only if they vie with targets for the control of action.     

Is age-related stability of subjective well-being a paradox? Cross-sectional and longitudinal evidence from the Berlin Aging Study

Subjective well-being is thought to remain relatively stable into old age despite health-related losses. Age and functional health constraints were examined as predictors of individual differences and intraindividual change in subjective well-being, as indicated by positive and negative affect, using cross-sectional (N = 516) and longitudinal (N = 203) samples from the Berlin Aging Study (age range 70-103 years). In cross-sectional and longitudinal analyses, age and functional health constraints were negatively related to positive affect but unrelated to negative affect. Cross-sectionally, controlling for functional health constraints reversed the direction of the relationship between age and positive affect and produced a negative association between age and negative affect. Findings suggest two qualifications to the average stability of overall subjective well-being: Only some dimensions of subjective well-being remain stable, while others decline; age per se is not a cause of decline in subjective well-being but health constraints are.