The structure of working memory abilities across the adult life span

The present study addresses three questions regarding age differences in working memory: (1) whether performance on complex span tasks decreases as a function of age at a faster rate than performance on simple span tasks; (2) whether spatial working memory decreases at a faster rate than verbal working memory; and (3) whether the structure of working memory abilities is different for different age groups. Adults, ages 20-89 (n = 388), performed three simple and three complex verbal span tasks and three simple and three complex spatial memory tasks. Performance on the spatial tasks decreased at faster rates as a function of age than performance on the verbal tasks, but within each domain, performance on complex and simple span tasks decreased at the same rates. Confirmatory factor analyses revealed that domain-differentiated models yielded better fits than models involving domain-general constructs, providing further evidence of the need to distinguish verbal and spatial working memory abilities. Regardless of which domain-differentiated model was examined, and despite the faster rates of decrease in the spatial domain, age group comparisons revealed that the factor structure of working memory abilities was highly similar in younger and older adults and showed no evidence of age-related dedifferentiation.     

Reading your own lips: Common-coding theory and visual speech perception

Common-coding theory posits that (1) perceiving an action activates the same representations of motor plans that are activated by actually performing that action, and (2) because of individual differences in the ways that actions are performed, observing recordings of one’s own previous behavior activates motor plans to an even greater degree than does observing someone else’s behavior. We hypothesized that if observing oneself activates motor plans to a greater degree than does observing others, and if these activated plans contribute to perception, then people should be able to lipread silent video clips of their own previous utterances more accurately than they can lipread video clips of other talkers. As predicted, two groups of participants were able to lipread video clips of themselves, recorded more than two weeks earlier, significantly more accurately than video clips of others. These results suggest that visual input activates speech motor activity that links to word representations in the mental lexicon.     

Effects of Age,Domain, and Processing Demands on Memory Span: Evidence for Differential Decline

Analysis of cross-sectional data from the normative sample of the Wechsler Memory Scale - Third Edition (WMS-III) revealed different patterns of age-related differences in memory span measures depending on the type of memory item, processing demands, and the age of the older adult group. Regression of memory span on age revealed that the slope for Spatial Span raw scores was significantly more negative than the slope for Digit Span raw scores. There was no significant difference, however, either between the slopes for forward and backward Digit Span or between the slopes for forward and backward Spatial Span. Regression of Letter-Number Sequencing raw scores on age showed a distinctive, curvilinear pattern. Taken together, the present findings suggest that at least two mechanisms are involved in age-related differences in memory span. One mechanism, associated with a relatively linear decrease in memory span as a function of age, may differentially affect the storage of different types of information (e.g., sequences of digits vs. spatial locations). The other mechanism, evidenced by the curvilinear trend in Letter-Number Sequencing scores, may be tentatively attributed to a decline in executive aspects of working memory that becomes increasingly pronounced with age.     

A discounting framework for choice with delayed and probabilistic rewards

When choosing between delayed or uncertain outcomes, individuals discount the value of such outcomes on the basis of the expected time to or the likelihood of their occurrence. In an integrative review of the expanding experimental literature on discounting, the authors show that although the same form of hyperbola-like function describes discounting of both delayed and probabilistic outcomes, a variety of recent findings are inconsistent with a single-process account. The authors also review studies that compare discounting in different populations and discuss the theoretical and practical implications of the findings. The present effort illustrates the value of studying choice involving both delayed and probabilistic outcomes within a general discounting framework that uses similar experimental procedures and a common analytical approach.     

Stammering and therapy views of people who stammer

This study used a postal questionnaire to seek the views of adults who stammer concerning the effect of stammering on their lives, the speech and language therapy and other remedies they have tried, and their hopes for speech and language therapy in the future. The 332 returned questionnaires indicated that stammering had the greatest adverse effect on school life and occupation. Speech and language therapy had been helpful to many, but the nature of the benefits and specific therapies used were not cited in many responses. An emergent theme in unhelpful therapy was the dissatisfaction that arises when individual needs are not met. In the future, people want help in controlling stammering and in developing coping strategies. The desire for timely and effective therapy for children, ongoing help and for group or intensive work has implications for service organization and therapist's skills. The survey highlights the need for therapists and clients to negotiate therapy aims and procedures that are clearly defined, appropriate to individual needs, achievable, and, if possible, recorded and measured. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to list (1) the areas most and least affected by stammering, (2) the therapy approaches respondents had found helpful, and (3) other remedies that tried to help stammering.     

Love's labor in the health care system: working toward gender equity

In this commentary on Eva Feder Kittay's Love's Labor: Essays on Women, Equality, and Dependency, I focus on Kittay's dependency theory. I apply this theory to an analysis of women's inadequate access to high-quality, cost-effective healthcare. I conclude that while quandaries remain unresolved, including getting men to do their share of dependency work, Kittay's book is an important and original contribution to feminist healthcare ethics and the development of a normative feminist ethic of care.     

Temporal discounting when the choice is between two delayed rewards

The present experiments extend the temporal discounting paradigm from choice between an immediate and a delayed reward to choice between 2 delayed rewards: a smaller amount of money available sooner and a larger amount available later. Across different amounts and delays, the data were consistently well described by a hyperbola-like discounting function, and the degree of discounting decreased systematically as the delay to the sooner reward increased. Three theoretical models (the elimination-by-aspects, present-value comparison, and common-aspect attenuation hypotheses) were evaluated. The best account of the data was provided by the common-aspect attenuation hypothesis, according to which the common aspect of the choice alternatives (i.e., the time until the sooner reward is available) receives less weight in the decision-making process.