Processing of threat-related information in rape victims

We investigated selective processing of threat information in persons with posttraumatic stress disorder (PTSD) by using a modified Stroop procedure. Subjects were 15 rape victims with PTSD, 13 rape victims without the disorder, and 16 nontraumatized control subjects. They were asked to name the color of four types of words: specific threat (rape-related) words, general threat (related to physical harm and death) words, neutral words, and nonwords. Rape victims with PTSD evidenced a longer response latency for color naming of rape-related words than for other target-word types. Response latencies of non-PTSD victims and nonvictim control subjects did not differ across word types. Possible mechanisms underlying the selective processing of threat material are considered, and clinical implications are discussed.     

Self-Efficacy,Perceptions of Success,and Intrinsic Motivation for Exercise1

A number of investigators have attempted to identify the determinants of continued participation in exercise regimens. Within a social cognitive framework, the present study examined the relationships among self-efficacy cognitions, perceptions of success, and multidimensional intrinsic motivation in the exercise domain. Multivariate analyses of variance indicated that highly efficacious individuals were more intrinsically motivated toward aerobic dance than were their less efficacious counterparts. However, multiple regression analyses revealed both perceptions of success and self-efficacy to account for significant variance in intrinsic motivation at both the composite and dimensional levels. Moreover, perceptions of success were considerably stronger predictors than were efficacy cognitions. The results are discussed in terms of the need for multiple measures of perceived success, the employment of longitudinal designs to determine the direction of causality among these variables, and possible implications for adherence issues.     

The interaction between stimulus and reinforcer control on remembering.

In a symbolic matching-to-sample task, 6 pigeons obtained food by pecking a red side key when the brighter of two white lights had been presented on the center key and by pecking a green side key when the dimmer of two white lights had been presented on the center key. Across Part 1 and Parts 6 to 10, the delay between sample-stimulus presentation and the availability of the choice keys was varied between 0 s and 25 s. Across Parts 1 to 5, the delay between the emission of a correct choice and the delivery of a reinforcer was varied between 0 s and 30 s. Although increasing both types of delay decreased stimulus discriminability, lengthening the stimulus-choice delay produced a greater decrement in choice accuracy than did lengthening the choice-reinforcer delay. Additionally, the relative reinforcer rate for correct choice was varied across both types of delay. The sensitivity of behavior to the distribution of reinforcers decreased as discriminability decreased under both procedures. These data are consistent with the view, based on the generalized matching law, that sample stimuli and reinforcers interact in their control over remembering.     

The role of esteem and coping in response to a threat communication

Two experiments examined the relations among self-esteem, perceived competency to cope, and actual coping behaviors following a threat communication. Leventhal's “parallel response model” (in Advances in experimental social psychology, L. Berkowitz (Ed.), New York: Academic Press, 1970, Vol. 5) predicts that low-esteem subjects will show deficits in both competency and coping behaviors. Experiment 1 manipulated threat level of a tetanus communication. Low-esteem subjects showed coping deficits on measures of free associations, free recall, fatalism, and coping. Threat groups differed only on fear and danger measures. Experiment 2 manipulated the fear level of an antismoking film and used false feedback to alter perceived competency. Positive feedback increased perceived competency to quit smoking among low-esteem subjects only. Without feedback, low-esteem subjects reduced smoking less than high-esteem subjects; positive feedback reversed the pattern. The discussion argued that, consistent with Leventhal's model, the low-esteem coping deficit has two independent causes: (1) excessive concern with fear, and (2) inadequate perceived competency.     

Chronic effects of electrical stimulation of muscle on the fractionated components of audio response time

Six male volunteer subjects underwent five weeks (15 sessions) of electrical stimulation (ES) of the triceps brachii muscle (medial head), participated in a pretest, and five weekly post-treatment performance tests of an elbow extension task. Response time (RSP) was electronically fractionated into the two components of reaction time (RT): premotor reaction time (PMT) and motor reaction time (MT): and movement time (MVT) for 45 degrees of elbow extension. Acceleration characteristics of the movement were quantified via a piezoelectric accelerometer mounted on a specially-built mechanism that allowed the desired motion in a transverse plane. Statistical analysis did not indicate significant treatment effects on the criterion measures, however, a significant linear trend for MT and significant linear and quadratic trends for MVT were indicated. Neuromuscular adaptation to the passage of electric current through nerve and muscle tissue was indicated by a significant quadratic trend and significant differences between all weekly accumulative (treatment) voltages. An unexpected significant negative correlation between PMT and MT was considered cause for further study. The particular technique of ES administration, although it produced consistant changes in RSP components (Ward and Grabiner 1981) was not as effective as methods described by other investigators for increased human performance.     

Stimulus discriminability in free-operant and discrete-trial detection procedures.

Six pigeons were trained to discriminate different light intensities in four experimental procedures. Experiment 1 compared stimulus discriminability in a yes-no signal-detection task with discriminability measures obtained from two free-operant procedures. Discriminability estimates were significantly lower in the detection procedure. Experiment 2 showed this lowered discriminability to be a function of the delay between stimulus presentation and the availability of the choice-response keys in the standard detection task. In addition, reinforcement sensitivity was lowest when correct choice responses were intermittently, rather than continuously, reinforced.     

Using computer conferencing to formulate a computer simulation of transitive behavior

The activities of a group engaged in simulation modeling via computer conferencing are described, and the model which resulted from those activities is briefly outlined. The phenomena which were modeled were initially described in a series of studies by Trabasso and his colleagues. These studies centered upon exhibition of transitive choices by children and adults, and supported the hypothesis that the choices were guided by formation of “linear arrays“ of the choice objects.