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.     

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.     

TEACHING CONVERSATION-RELATED SKILLS TO PREDELINQUENT GIRLS1

The use of conversation-related skills by youthful offenders can influence social interactions with adults. These behaviors are also likely to be useful to adolescents after their release from a treatment program (Journal of Applied Behavior Analysis, 1972, 5 , 343–372). Four girls, aged 13 to 15 yr, residing at Achievement Place for Girls in Lawrence, Kansas, received training on conversation-related behaviors. A multiple-baseline design across youths and across behaviors was used. Youth answer-volunteering in response to questions and three youth nonverbal components (“hand on face”, “hand at rest”, and “facial orientation”) were measured during daily 10-min sessions with a simulated guest in the group home's living room. Answer-volunteering was scored each session as the per cent of 13 “secondary” questions that the simulated guest did not have to ask following 10 “primary” questions. The three nonverbal components were scored according to their occurrence during 10-sec intervals and the resultant scores were averaged per session for an overall appropriate nonverbal score. The girls individually earned points within the home's token economy for participating in each session and additional points were awarded after training if preselected behavioral criteria were achieved for each of the two behavior categories per girl. Some of the training sessions were led by a “teaching-parent” (specially trained houseparent) while others were led by individual girls. Point consequences were administered by both the teaching-parent and by the “peer-trainers”. The average observed rate of answer-volunteering by the girls during pretraining sessions was 30% for S₁, 30% for S₂, 23% for S₃, and 68% for S₄. The average rate of answer-volunteering during posttraining sessions was: S₁ = 92%, S₂ = 89%, S₃ = 90%, and S₄ = 98%. The average nonverbal score during pretraining sessions was 82% for S₁, 53% for S₂, 60% for S₃, and 82% for S₄. The average nonverbal score during posttraining sessions was: S₁ = 98%, S₂ = 98%, S₃ = 98%, and S₄ = 100%. Videotapes of the sessions were shown in a random sequence to four adults (probation officer, social worker, etc who represented “significant others” for the youths' future success in the community. The adults judged posttraining tapes on the average as more appropriate 100% of the time for S₁, 100% of the time for S₂, 90% of the time for S₃, and 70% of the time for S₄. The study demonstrated that training of conversation-related skills is feasible with predelinquent girls, that the girls can help train each other, and that social validation of the training results is possible.     

TEACHING PEDESTRIAN SKILLS TO RETARDED PERSONS: GENERALIZATION FROM THE CLASSROOM TO THE NATURAL ENVIRONMENT1

Little attention has been given to teaching adaptive community skills to retarded persons. In this study, five retarded male students were taught basic pedestrian skills in a classroom. Training was conducted on a model built to simulate city traffic conditions. Each subject was taught five specific skills involved in street crossing in sequence, viz. intersection recognition, pedestrian-light skills, traffic-light skills, and skills for two different stop-sign conditions. Before, during, and after training, subjects were tested on generalization probes on the model and under actual city traffic conditions. Results of a multiple-baseline design across both subjects and behaviors indicated that after receiving classroom training on the skills, each subject exhibited appropriate pedestrian skills under city traffic conditions. In addition, training in some skills appeared to facilitate performance in skills not yet trained.     

Reappraising the link between peritraumatic dissociation and PTSD symptom severity: evidence from a longitudinal study of community violence survivors

Cross-lagged panel analysis of longitudinal data collected from young adult survivors of community violence was used to examine the relationship between recall of peritraumatic dissociation and posttraumatic stress disorder (PTSD) symptom severity. Recollections of peritraumatic dissociation assessed within days of exposure differed from recollections measured at 3- and 12-month follow-up interviews. Peritraumatic dissociation was highly correlated with PTSD symptoms within each wave of data collection. Baseline recollections of peritraumatic dissociation were not predictive of follow-up PTSD symptom severity after controlling for baseline PTSD symptom severity. This pattern of results replicates previous work demonstrating a correlation between peritraumatic dissociation and subsequent symptom severity. However, findings are not consistent with the prevailing view that peritraumatic dissociation leads to increased PTSD symptom severity.     

Mental simulation inflates performance estimates for physical abilities

In five experiments, we examined how mental simulation of physical activities affected estimates of one's ability to perform the same activities. In Experiment 1, participants who simulated lifting aheavy object estimated that they could lift more weight than did participants who did not perform the simulation. In Experiment 2A, the frequency with which participants performed the simulation exercises was manipulated. In Experiments 2B and 2C, we manipulated the amount of weight that people simulated lifting in order to address potential alternative explanations of the inflation effect. In Experiment 3, mental simulations were manipulated within subjects. In all the experiments, the simulated events showed inflated estimates, as compared with nonsimulated events. These results were interpreted in the context of the misattribution-of-familiarity account of imagination inflation.     

Enhancement of auditory fear conditioning after housing in a complex environment is attenuated by prior treatment with amphetamine

Prior exposure to drugs of abuse has been shown to occlude the structural plasticity associated with living in a complex environment. Amphetamine treatment may also occlude some cognitive advantages normally associated with living in a complex environment. To test this hypothesis we examined the influence of prior exposure to amphetamine on fear conditioning in rats housed in either a standard or complex environment. Housing in a complex environment facilitated fear learning to an auditory conditioned stimulus (CS), but not to the training context, relative to animals housed singly or in a social group. Prior treatment with amphetamine eliminated this effect. These results indicate that living in a complex environment facilitates conditional freezing to an auditory CS, and that this effect is abolished by pretreatment with amphetamine.