Mechanisms of visual-cognitive aging: A neural network account

Two neural network simulations were run for the purpose of specifying the network parameters that best describe age-related interindividual and intraindividual variability in figure completion performance. the network architecture was modified in three ways that corresponded to plausible computational and neuro-anatomical constraints. In two simulations in which the rate of increase of activation within network units was constrained during testing, the performance of the network closely resembled the relevant empirical data. These findings supported a computationally specific model of age-related differences in figure completion performance rather than a diffuse model of age-related slowing. It is suggested that the analysis of fit between the results of computer simulations and analogous empirical data provides a useful method for the explication of aging mechanisms, and for distinguishing among competing hypotheses and constructs in the study of cognitive aging.     

Differential Automatic Processing Deficits in Early Stage Alzheimer's Disease

This experiment sought further support for the view that early stage Alzheimer's disease (AD) disrupts cognitive structures that cast experience into a temporal framework. Forty participants, evenly divided between normal elderly (NE) and persons diagnosed with mild AD, viewed 19 lists of 14 pictures each. Following the presentation of each list participants were asked to identify the most recently experienced picture (target) from 3 pictures. A second stimulus was a picture never previously seen; the third picture was a distracting item that had appeared in the list on either one or three occasions. The results show that whereas choice accuracy of the NE group remained largely unimpaired regardless of the delay between the target and the judgment task or the frequency of the distractor, the AD participants exhibited large and profound deficits in temporal judgments, especially when distractor frequency was greater than the more recent event. In effect, the AD group relied on how often an event occurred rather than the time of its occurrence. This finding is consistent with previous research that found AD patients deficient in forming a temporal representation of their experience.     

Space Fortress game training and executive control in older adults: A pilot intervention

ABSTRACT

We investigated the feasibility of using the Space Fortress (SF) game, a complex video game originally developed to study complex skill acquisition in young adults, to improve executive control processes in cognitively healthy older adults. The study protocol consisted of 36 one-hour game play sessions over 3 months with cognitive evaluations before and after, and a follow-up evaluation at 6 months. Sixty participants were randomized to one of three conditions: Emphasis Change (EC) – elders were instructed to concentrate on playing the entire game but place particular emphasis on a specific aspect of game play in each particular game; Active Control (AC) – game play with standard instructions; Passive Control (PC) – evaluation sessions without game play. Primary outcome measures were obtained from five tasks, presumably tapping executive control processes. A total of 54 older adults completed the study protocol. One measure of executive control, WAIS-III letter–number sequencing, showed improvement in performance from pre- to post-evaluations in the EC condition, but not in the other two conditions. These initial findings are modest but encouraging. Future SF interventions need to carefully consider increasing the duration and or the intensity of the intervention by providing at-home game training, reducing the motor demands of the game, and selecting appropriate outcome measures.     

Neuropsychological and neurophysiological effects of strengthening exercise for early dementia: A pilot study

ABSTRACT

Research demonstrates a positive effect of aerobic exercise on cognitive functioning in older adults. Unfortunately, aerobic exercise is often contraindicated for older adults due to cardiovascular and functional limitations. Low-intensity strengthening exercise may offer a practical alternative, but the neuropsychological benefits and potential neurophysiological mechanisms are less well understood. The current study evaluated the effects of a 10-week strengthening exercise intervention on cognitive functioning and EEG in a sample of 13 older adults with early dementia, and 9 normative controls. Results revealed beneficial effects of strengthening exercise on verbal memory coupled with frontal beta and delta power asymmetries and N200 amplitude asymmetry. Results point to increased cognitive efficiency following 10 weeks of strengthening exercise. The findings suggest it is feasible to conduct a strengthening intervention with early dementia patients, and to gather neuropsychological and neurophysiological data to evaluate outcomes. Strengthening exercise may serve as a useful alternative to aerobic exercise.     

Daily Functioning, Health Status, and Happiness in Older Adults

The hypothesis that the degree to which disease disrupts daily functioning is inversely associated with happiness is widely accepted, yet existing literature offers little direct evidence in its support. This paper explores the hypothesized association in a community-based sample of 383 older adults. To assess the degree to which disease disrupts daily functioning we developed a measure—called the freedom-from-debility score—based on four Short Form-12 (SF-12) Health Survey questions explicitly designed to represent “limitations in physical activities because of health problems” and “limitations in usual role activities because of physical health problems.” The results were consistent with the hypothesis. When participants were divided into categories based on their freedom-from-debility score, median happiness scores were monotonically increasing across categories. Controlling for demographic and socio-economic factors as well as health status (measured both subjectively and objectively), a one-point increase in freedom-from-debility score (on a scale from 0 to 100) was associated with a three-percent reduction in the odds of lower-quartile happiness. The results support the contention that health status is one of the most influential predictors of happiness, that the association between health status and happiness depends greatly on the manner in which health status is measured, and that the degree to which disease disrupts daily functioning is inversely associated with happiness.     

Preconceptual intelligibility in perception

This paper argues that John McDowell’s conceptualism distorts a genuine phenomenological account of perception. Instead of the seemingly forced choice between conceptualism and non-conceptualism as to what accounts for perceptual and discursive meaning, I provide an argument that there is a preconceptual intelligibility already in the perceptual field. With the help of insights from certain nonconceptualists I sketch out an argument that there is a teleological directedness in the way in which latent order and structure can be discriminated at the level of perceptual content. This content can then be brought to discursive, conceptual clarity by understanding in such a way that it is guided by the order already discovered in perception. With the help of Husserlian phenomenology of perception, I argue that the fundamental roots of epistemic normativity lie in the discriminating intelligence or mindedness operative below the level of the explicitly conceptual. By preconceptual is meant the directedness of explication of the structures present in the sensory manifold toward fully explicit conceptual judgments.     

A Group of Sexually Abused Adolescents' Perceptions of their Future Life-Roles: An Exploratory Study

Sexual abuse of adolescents can have detrimental effects on their perceptions of their different future life-roles. We investigated such perceptions of students with a history of sexual abuse (n=163) as well as typically developing others (n=237). Participants completed the Life-role Inventory of the then called Human Sciences Research Council (Langley, 1990). Between-group comparisons were carried out. Adolescents with a history of sexual abuse reported negative perceptions of themselves fulfilling some of their roles in the future, being committed to these roles and attaching value to them, compared to typically developing others.     

Spatial interference between attended items engenders serial visual processing

A pair of experiments investigated the architecture of visual processing, parallel versus serial, across high and low levels of spatial interference in a divided attention task. Subjects made speeded judgments that required them to attend to a pair of color-cued objects among gray filler items, with the spatial proximity between the attended items varied to manipulate the strength of interference between attended items. Systems factorial analysis (Townsend & Nozawa, Journal of Mathematical Psychology 39:321-359, 1995) was used to identify processing architecture. Experiment 1, using moderately dense displays, found evidence of parallel processing whether attended objects were in low or high proximity to one another. Experiment 2, using higher-density displays, found evidence of parallel selection when attended stimuli were widely separated but serial processing when they were in high proximity. Divided visual attention can operate in parallel under conditions of low or moderate spatial interference between selected items, but strong interference engenders serial processing.     

A test of two methods of arithmetic fluency training and implications for educational practice

Children are exposed to multiple training tasks that are intended to support acquisition of basic arithmetic skills. Surprisingly, there is a scarcity of experimental research that directly compares the efficacy of those tasks, raising the possibility that children may be spending critical instructional time on tasks that are not effective. We conducted an experiment with 1st through 6th grade children comparing two arithmetic training tasks that are widely used: answer production training and fact triangle training. Results show that answer production training produces substantial fluency gains, whereas fact triangle training does not. Further, we show that, despite theoretical considerations that suggest otherwise, fact triangle training does not produce more flexibly applicable learning. Implications for memory representation, arithmetic fluency training, and broader educational strategy are discussed.