Exercise as a buffer of life stress: a prospective study of adolescent health

The hypothesis that physical exercise provides benefits to individuals under periods of life stress has rarely been subject to empirical verification. This article presents the results of a longitudinal study of stress and well-being in adolescence in which the ability of exercise to buffer stress-induced deteriorations in physical health was examined. In accordance with predictions, prospective analyses revealed that the negative impact of stressful life events on health declined as exercise levels increased. These findings suggest that exercise may be a valuable resource for combating life stress. Discussion centers on possible mediating mechanisms and on the practical implications of the results.     

Effects of reinforcement context on choice

Two experiments investigated the effects of successive reinforcement contexts on choice. In the first, concurrent variable-interval schedules of primary reinforcement operated during the initial links of concurrent chains. The rate of this reinforcement arranged by the concurrent schedules was decreased across conditions: When it was higher than the terminal-link rate, preference for the higher frequency initial-link schedule increased relative to baseline. (During baseline, a standard concurrent-schedule procedure was in effect). When the initial-link reinforcement rate was lower than the terminal-link rate, preference converged toward indifference. In the second experiment, a chain schedule was available on a third key while a concurrent schedule was in effect on the side keys. When the terminal link of the chain schedule was produced, the side keys became inoperative. Availability of the chain schedule did not affect choice between the concurrent schedules. These results show that only when successive reinforcement contexts are produced by choice responding do those successive contexts affect choice in concurrent schedules.     

The associative basis of contingent color aftereffects.

According to a conditioning analysis of the orientation-contingent color aftereffect (McCollough effect, ME), orientation stimulus (grids) become associated with color. Contrary to this interpretation are reports that simple forms cannot be used to elicit illusory color and that the ME is not degraded by decreasing the grid-color correlation. The present results indicate: (a) Form stimuli can contingently elicit color aftereffects; (b) even a non-patterned stimulus--the lightness of a frame surrounding a colored area--can contingently elicit color aftereffects; (c) this frame lightness-contingent aftereffect, like the ME, persists for at least 24 hr; and (d) the frame lightness-contingent aftereffect can be used to demonstrate that correlational manipulations affect the ME, as they affect other types of conditional responses.     

Inconsistent communication: A simplified method for selecting messages

In examining the family's role in the development and perpetuation of disordered behavior, studies of inconsistent communication have focused on the frequency and impact of such communications in disturbed versus non-disturbed groups. For these and other lines of study, current methods for defining and selecting inconsistent messages are extremely time-consuming, and as a result, large-scale efforts have been discouraged. To address this problem, the current study attempted to develop and evaluate an efficient procedure for selecting inconsistent communications which would be comparable to the standard method. Most important, it was found that raters are capable of accurately judging affect in a particular channel when presented with several channels simultaneously, and as such, it is unnecessary to artificially separate channels when affect ratings are to be obtained. Future research should be facilitated by the method developed in the current study.     

The Social Phobia and Anxiety Inventory: concurrent validity with a clinic sample

The Social Phobia and Anxiety Inventory (SPAI) is an empirically derived self-report inventory developed as a specific measure of social phobia. The current investigation included two studies. The first examined the correlation of the SPAI with daily social behavior of a clinic sample of social phobics. The results indicated that the SPAI provides a reasonable indication of the distress experienced during daily social encounters in three dimensions: behavior, cognitions, and overall distress. The second study examined the validity of the SPAI with reference to the somatic response and avoidance behavior of social phobics. The results indicated that the somatic items of the SPAI are related to the somatic response of social phobics and that performance on the SPAI is associated with avoidance behavior in an anxiety-producing task.     

Information processing abilities and performance on two perceptual-motor tasks

The purpose of this study was to investigate whether the hypothesized information-processing mechanisms, thought to be reflected by the slope and intercept of the regression of choice reaction time on stimulus information or information transmitted could account for performance on two novel laboratory tasks. In addition, analyses were performed to determine whether these theorized mechanisms represent stable within individual abilities or task specific capabilities. Analysis indicated that the slopes obtained from two different choice reaction time paradigms were unrelated while intercepts were moderately correlated. Examination of the pattern of zero-order correlations further showed that regression components were not meaningfully related to performance on either novel task, suggesting that knowledge of information-processing mechanisms, as assessed in choice RT paradigms, did not enhance the understanding of performance in more complex tasks.