Identifying subgroups that succeed or fail with three levels of physical activity intervention: the Activity Counseling Trial.

The authors used recursive partitioning methods to identify combinations of baseline characteristics that predict 2-year physical activity success in each of 3 physical activity interventions delivered in the multisite Activity Counseling Trial. The sample consisted of 874 initially sedentary primary care patients, ages 35-75 years, who were at risk for cardiovascular disease. Predictors of 2-year success were specific to each intervention and represented a range of domains, including physiological, demographic, psychosocial, health-related, and environmental variables. The results indicate how specific patient subgroups (e.g., obese, unfit individuals; high-income individuals in stable health) may respond differently to varying levels and amounts of professional assistance and support. The methods used provide a practical first step toward identifying clinically meaningful patient subgroups for further systematic investigation.     

The effects of self‐explaining when learning with text or diagrams

Self‐explaining is an effective metacognitive strategy that can help learners develop deeper understanding of the material they study. This experiment explored if the format of material (i.e., text or diagrams) influences the self‐explanation effect. Twenty subjects were presented with information about the human circulatory system and prompted to self‐explain; 10 received this information in text and 10 in diagrams. Results showed that students given diagrams performed significantly better on post‐tests than students given text. Diagrams students also generated significantly more self‐explanations that text students. Furthermore, the benefits of self‐explaining were much greater in the diagrams condition. To discover why diagrams can promote the self‐explanation effect, results are interpreted with reference to the multiple differences in the semantic, cognitive and affective properties of the texts and diagrams studied.     

Reciprocal Relationships between Leader–Member Exchange (LMX) and Job Satisfaction: A Cross‐Lagged Analysis

While previous research has mainly emphasised the importance of leader–member exchange (LMX) to job satisfaction, there is a lack of research on reciprocal relationships between job satisfaction and LMX. In this study, we not only suggest that good LMX increases job satisfaction, but that job satisfaction can also enhance high‐quality supervisor–employee relationships. A full cross‐lagged panel analysis was used to test reciprocal relationships between LMX and job satisfaction. Employees (N= 279) of a large information technology company filled out questionnaires at two times, with a time lag of 3 months. In line with our predictions, findings revealed a positive relationship between LMX and job satisfaction both at Time 1 and Time 2. Moreover, LMX at Time 1 predicted the increase of job satisfaction at Time 2, and job satisfaction at Time 1 predicted the increase of LMX at Time 2. The results demonstrate the need to consider reciprocal relationships between job satisfaction and LMX when explaining employees' workplace outcomes. Our findings are discussed in terms of positive psychology theory.     

Smoking, caffeine, and stress: effects on blood pressure and heart rate in male and female college students

This study examined the independent and joint effects of cigarette smoking and caffeine consumption on blood pressure (BP) and heart rate (HR) reactions to stress in male and female college students. Following an initial physiological baseline, participants received one of four experimental treatments (paced smoking, caffeine, smoking plus caffeine, or neither) and had BP and HR measured before, during, and after two stressful tasks. The results revealed that, compared with the control condition, caffeine ingestion enhanced the magnitude of stress-induced systolic BP and HR reactions. Smoking combined additively with stress, and the joint effect of smoking and caffeine was no greater than either taken alone. Males and females were generally similar in their BP and HR responses to smoking, caffeine, and stress. Inconsistencies with previous research and possible physiological mechanisms underlying the observed effects are discussed.     

On the self-serving function of social anxiety: shyness as a self-handicapping strategy

We tested the hypothesis that socially anxious or shy individuals use their anxiety symptoms as a strategy to control attributions made about their performances in social-evaluative settings (i.e., self-handicapping strategies). Specifically, we predicted that trait-socially anxious or shy persons would report more symptoms of social anxiety in an evaluative setting in which anxiety or shyness could serve as an excuse for poor performance than would individuals in (a) an evaluative setting in which shyness was precluded as an excuse or (b) a nonevaluative setting. Furthermore, we predicted that this self-protective pattern of symptom reporting would not occur for individuals who were not trait-socially anxious because these persons would not commonly use such symptoms as a self-handicapping strategy. Results supported these predictions for male subjects, but not for female subjects. Sex differences in the strategic use of shyness are discussed in relation to other research on sex differences in the etiology and correlates of social anxiety.     

A hardware and software interface for sensing changes in rotary position with an Apple II microcomputer

A design for an Apple II interface that senses relative rotary position and/or motion via a digital potentiometer is presented. A thorough discussion of the circuit’s theory of operation and a fully commented BASIC software listing are included. Suggested applications include an infinite-turn rotary device for psychophysical methods of adjustment, the sensing of rotary translations of a steering wheel in a driving simulator, and a digital tachometer/odometer for tracking performance on stationary exercise bicycles and treadmills.     

Perception of structure in novel music

Two experiments demonstrated the way in which musicians and nonmusicians process realistic music encountered for the first time. A set of tunes whose members were related to each other by a number of specific musical relationships was constructed. In Experiment 1, subjects gave similarity judgments of all pairs of tunes, which were analyzed by the ADDTREE clustering program. Musicians and nonmusicians gave essentially equivalent results: Tunes with different rhythms were rated as being very dissimilar, whereas tunes identical except for being in a major versus a minor mode were rated as being highly similar. In Experiment 2, subjects learned to identify the tunes, and their errors formed a confusion matrix. The matrix was submitted to a clustering analysis. Results from the two experiments corresponded better for the nonmusicians than for the musicians. Musicians presumably exceed nonmusicians in the ability to categorize music in multiple ways, but even nonmusicians extract considerable information from newly heard music.