The difference engine: A model of diversity in speeded cognition

A theory of diversity in speeded cognition, the difference engine, is proposed, in which information processing is represented as a series of generic computational steps. Some individuals tend to perform all of these computations relatively quickly and other individuals tend to perform them all relatively slowly, reflecting the existence of a general cognitive speed factor, but the time required for response selection and execution is assumed to be independent of cognitive speed. The difference engine correctly predicts the positively accelerated form of the relation between diversity of performance, as measured by the standard deviation for the group, and task difficulty, as indexed by the mean response time (RT) for the group. In addition, the difference engine correctly predicts approximately linear relations between the RTs of any individual and average performance for the group, with the regression lines for fast individuals having slopes less than 1.0 (and positive intercepts) and the regression lines for slow individuals having slopes greater than 1.0 (and negative intercepts). Similar predictions are made for comparisons of slow, average, and fast subgroups, regardless of whether those subgroups are formed on the basis of differences in ability, age, or health status. These predictions are consistent with evidence from studies of healthy young and older adults as well as from studies of depressed and age-matched control groups.     

Practical Memory Concerns of Older Adults

We examine practical memory concerns in a sample of community-dwelling older adults. Participants responded to open-ended questions that were designed to solicit information regarding memory self-efficacy, memory management, memory remediation, and fears about memory aging in adulthood. Results indicated that (a) important dates, such as birthdays and anniversaries, were easily remembered, but names were not; (b) external memory aids were used most frequently; (c) a desire to improve memory for names and certain types of verbal information was expressed; and (d) loss of independence emerged as a fear associated with memory aging. Implications of these findings for the design of strategies to improve everyday memory performance and clinical memory management in older adults are discussed.     

Mother Knows Best? Mother and Child Report of Behavioral Difficulties of Children of HIV-Infected Mothers

Children of HIV-infected mothers have more psychosocial adjustment difficulties than do those of noninfected mothers. In this study, child psychosocial adjustment in children of HIV-infected women is examined across the three stages of HIV-infected: asymptomatic, symptomatic and AIDS. Participants were 99 HIV-infected women and 148 noninfected women. Children were not identified as being HIV infected. Mother and child reports of behavioral difficulties are compared, and competing hypotheses about mother report of child behavior difficulties are tested. Results indicate an ascending linear trend for child report of internalizing and externalizing difficulties from the noninfected stage through increasingly severe stages of HIV-infection. According to mother report, child externalizing and internalizing difficulties are nonlinear, as mothers report an increase through the infected symptomatic stage, then a decrease in the AIDS stage. Implications for assessment, prevention and intervention in families with maternal HIV infection are discussed.     

The Utility of Problem-solving Training that Emphasises Selfmanagement Principles

This study examined the usefulness of an 8-week applied problem-solving training program. Specifically, the study examined (a) whether problem-solving training that emphasised self-management principles would be useful, (b) if the effects of training would persist over time, (c) whether an individual difference variable (problem-solving appraisal) would affect training outcomes, and (d) whether the cognitive responses of the subjects during the course of training were related to their problem-solving appraisal or the change process. Results indicated that problem solving training was effective at enhancing students’ problem-solving appraisal, and that the self-report changes were maintained at a 1 year follow-up. In particular, training seemed most useful for students who initially appraised their problem solving very negatively. Finally, the results suggested that the process-oriented cognitive responses were related to students' initial problem-solving self-appraisal as well as the impact of training. Implications of the results are discussed in terms of counselling interventions, problem solving training, the interpersonal influence process, and future research.     

The role of attentional biases in PTSD: is it interference or facilitation?

Although attentional biases have been demonstrated in individuals with posttraumatic stress disorder (PTSD), the cognitive methodologies used have not allowed for disambiguation of two types of attentional biases. It remains unclear if PTSD involves difficulty disengaging attention from threatening stimuli (interference) or facilitated detection. To differentiate between attentional interference and facilitation, 57 male Vietnam-era veterans (30 High PTSD and 27 Low PTSD) completed a visual search task with a lexical decision component. High PTSD veterans who engaged in the interference task first showed increased interference to threat-relevant words relative to Low PTSD veterans. However, no evidence was found for facilitated detection of threatening stimuli in PTSD.     

Biased processing of emotional information in girls at risk for depression

Researchers have documented that children of depressed mothers are at elevated risk for developing a depressive disorder themselves. There is currently little understanding, however, of what factors place these children at elevated risk. In the present study, the authors investigated whether never-disordered daughters whose mothers have experienced recurrent episodes of depression during their daughters' lifetime are characterized by biased processing of emotional information. Following a negative mood induction, participants completed an emotional-faces dot-probe task. Daughters at elevated risk for depression, but not control daughters of never-disordered mothers, selectively attended to negative facial expressions. In contrast, only control daughters selectively attended to positive facial expressions. These results provide support for cognitive vulnerability models of depression.     

How Do You Say Nature?: Opening the Design Space with a Knowledge Environment

In this paper, we describe a design study on how families in Los Angeles experience nature, with a particular focus on how using alternative formats for research analysis and presentation can enrich a design research inquiry. Conducted in Pasadena, CA as a part of Super Studio, the year-long design research class emphasized knowledge building and sharing through design methods of analysis, exhibition, and concept prototypes. After conducting interviews and engaging participants with probes, the class built the results into an open-ended knowledge environment. The main observation from the exhibition – that Angelenos have a limited vocabulary for describing nature and their interaction with it – helped to define the opportunity for design intervention that created connection points between Angelenos and nature. There are few attempts to describe how probe returns evolve into design concepts. Showcased is a process that depends on the unique affordances of design as the vehicle for discovery and invention.     

Identification variability as a measure of loudness: an application to gender differences.

It is well known that discrimination response variability increases with stimulus intensity, closely related to Weber's Law. It is also an axiom that sensation magnitude increases with stimulus intensity. Following earlier researchers such as Thurstone, Garner, and Durlach and Braida, we explored a new method of exploiting these relationships to estimate the power function exponent relating sound pressure level to loudness, using the accuracy with which listeners could identify the intensity of pure tones. The log standard deviation of the normally distributed identification errors increases linearly with stimulus range in decibels, and the slope, a, of the regression is proportional to the loudness exponent, n. Interestingly, in a demonstration experiment, the loudness exponent estimated in this way is greater for females than for males.