Individual consistencies in behavior: achievement persistence interactions as personality styles

Two experiments were carried out to find within-subject consistencies as well as individual differences in a choice situation involving achievement persistence. Four volunteers, two men (21 and 23 years old) and two women (21 and 22 years old) were exposed twice, with a 1-mo. interval, to a filling-patterns task, to evaluate their choices for two options. For one option, task-time and outcomes for every response were constant. For the other option, task-time decreased in correlation with an increase in earnings for every response. Analyses showed reliable profiles for three of the four subjects when percent of responding to each option was compared in independent experiments. Results are discussed in terms of interactive styles.     

Usability and Utility of a Computerized Cognitive-Behavioral Self-Help Program for Public Speaking Anxiety

This study describes the use of a cognitive-behavioral computer-administered self-help program with minimal therapist contact for public speaking anxiety. Participants (N = 10) with social phobia, as measured by a structured clinical interview, completed the self-help program in an open clinical trial. The program was delivered via a CD-ROM during individual sessions at an outpatient clinic, including 4 sessions of psychoeducation/cognitive therapy and 4 sessions of exposure therapy using a virtual audience presented on a computer screen. A therapist was available in another room to answer questions and to debrief for up to 10 minutes after each session. Participants completed standardized self-report questionnaires assessing social anxiety at pretreatment, posttreatment, and 3-month follow-up. Participants also completed measures of computer usability. Results showed decreases on all self-report measures of social anxiety from pre- to posttreatment, which were maintained at follow-up (n = 8). Participants also reported that they were satisfied with treatment, that they felt improved after treatment, and that the computer program was user-friendly. This study provides preliminary evidence that a computer-administered cognitive-behavioral-based program that includes minimal therapist contact may reduce public speaking anxiety and suggests that further research with a controlled design is needed.     

Cross-Sectional Analysis of Longitudinal Mediation Processes

Statistical mediation analysis can help to identify and explain the mechanisms behind psychological processes. Examining a set of variables for mediation effects is a ubiquitous process in the social sciences literature; however, despite evidence suggesting that cross-sectional data can misrepresent the mediation of longitudinal processes, cross-sectional analyses continue to be used in this manner. Alternative longitudinal mediation models, including those rooted in a structural equation modeling framework (cross-lagged panel, latent growth curve, and latent difference score models) are currently available and may provide a better representation of mediation processes for longitudinal data. The purpose of this paper is twofold: first, we provide a comparison of cross-sectional and longitudinal mediation models; second, we advocate using models to evaluate mediation effects that capture the temporal sequence of the process under study. Two separate empirical examples are presented to illustrate differences in the conclusions drawn from cross-sectional and longitudinal mediation analyses. Findings from these examples yielded substantial differences in interpretations between the cross-sectional and longitudinal mediation models considered here. Based on these observations, researchers should use caution when attempting to use cross-sectional data in place of longitudinal data for mediation analyses.     

A Comprehensive Decision Approach for Rubber Tree Planting Management in Africa

The main objective of this study is to settle a rigorous field of decision analysis for rubber tree clones selection. Nowadays, there does not exist any process based upon a rigorous method to select the best clone to be plant in order to get the highest return on investment. The only known selection method is to use the experience of different protagonists acting in the plantation. So, we need a tool that takes into account very important criteria in order to achieve the main objective. This goal is achieved by using multicriterion analysis methods to the clone selection. The ranking procedure uses Elimination and Choice Expressing the Reality (ELECTRE III). For each criterion, indifference and preference thresholds are determined after establishing the relative importance of each criterion including rubber tapping, cumulative production during 15 years, cumulative production between 15 and 25 years, wind resistance, disease resistance, physiological resistance, grafting and quality of the rubber. Copyright © 2011 John Wiley & Sons, Ltd.     

Gender dimorphic effects of voluntary running in laboratory rats depends on maturational status

This study examined the effect of 24?hr per day wheel access on running, body weight, and food intake for 30- or 50-day-old male and female rats under ad lib feeding conditions. Food intake and body weight were also monitored in a control group housed without access to running wheels. A dimorphic effect was observed after wheel introduction in 50-day-old but not 30-day-old rats: A temporary decline in food intake and a lasting decrease in body weight occurred for active male rats in comparison to their sedentary controls, and wheel access facilitated food intake and preserved body weight gain in female rats in comparison to their sedentary counterparts. Hyperphagia in adult females is interpreted in terms of the evolutionary acquired advantage linked to their reproductive function.     

Exploring task-set reconfiguration with random task sequences

Switching between two different tasks normally results in an impairment in people's performance known as a switch cost, typically measured as an increase in reaction time (RT) and errors compared to a situation in which no task switch is required. Researchers in task switching have suggested that this switch cost is the behavioural manifestation of the task set reconfiguration processes that are necessary to perform the upcoming task. However, an examination of the literature in task switching reveals apparently contradictory results about the nature of task set reconfiguration processes. In Experiment 1, we addressed this issue by comparing participants' performance in two different experimental conditions: predictable task switching and random task switching. In the predictable switch condition the switch cost completely vanished after the first repetition of the new task. However, in the random switch condition, while the difference between switch and repetition trials was not significant, we observed a significant reduction in RT between the first and second repetition of the new task. In Experiment 2, we further investigated the pattern of task set reconfiguration in the random switch situation. The results showed a progressive reduction of participants' response latencies across repetitions of the same task. The present study demonstrates that, whereas the results in predictable switching conditions are compatible with an exogenous-reconfiguration hypothesis, random task switching produces a more gradual, decay-like switch cost reduction with task repetition.     

What needs to be explained to account for age-related effects on multiple cognitive variables?

Structural equation methodology was used to investigate age-related influences across a number of cognitive variables in 204 adults ranging from 18 to 91 years of age with a hierarchical structure that contained 4 1st-order factors and 1 2nd-order common factor. Direct age relations were found to the common factor as well as to 1st-order speed and memory factors. Replicability of the findings was explored by investigating the same structure of age relations, using 2 different data sets, and a similar patten was found in each. These results suggest that at least 3 statistically distinct types of age-related influences are operating on a wide variety of cognitive variables and presumably require separate explanatory mechanisms.