Signaling in large-scale neural networks

We examine the recent finding that neurons in spinal motor circuits enter a high conductance state during functional network activity. The underlying concomitant increase in random inhibitory and excitatory synaptic activity leads to stochastic signal processing. The possible advantages of this metabolically costly organization are analyzed by comparing with synaptically less intense networks driven by the intrinsic response properties of the network neurons.     

Body dissatisfaction and body comparison with media images in males and females

This study examined the role of media body comparison as a mediator of the relationships between psychological factors and sociocultural pressures to be thin and body dissatisfaction in both females and males. Participants were 1,386 females (mean age = 19.37 years) and 1,130 males (mean age = 19.46) from diverse backgrounds who completed a self-report questionnaire. Path analysis was used to test a cross-sectional model in which media body comparison mediated the impact of self-esteem, depressive mood, parent dieting environment, friend dieting, TV exposure, magazine message exposure, weight teasing and body mass index (BMI) on body dissatisfaction. In females, media body comparison partially or fully mediated relationships between self-esteem, depressive mood, friend dieting, magazine message exposure and BMI, and body dissatisfaction. In males, media body comparison was not a significant predictor of body dissatisfaction. This research particularly highlights the need to further examine processes that are involved in the development of body dissatisfaction in males.     

Attraction and exchange in continuing and noncontinuing dating relationships

Measures enabling one to assess general feelings about a relationship, social exchange behaviors, and the particularism and symbolism of resources given to and received from another were examined longitudinally in 38 dating couples. These variables were first measured shortly after a couple began to date and again approximately 4 months later. We found that in contrast to what might be expected from prevailing theories of relationship development, the later status of couples (still dating or broken up) could be predicted with a high degree of accuracy from the initial measures. This finding corroborates and extends previous work dealing with same-sex friendships. Couples who were still dating 4 months later demonstrated greater love, more relationship-maintaining behaviors, more favorable evaluations of the dating relationship, and greater amounts of self-disclosure at the time of initial contact than did couples who broke up. Over time, these differences (as well as others) between couples who did and who did not continue dating intensified. In terms of the types of resources subjects gave and received from their dating partner, more particularistic and more symbolic resources were exchanged in continuing couples only later. Although both continuing and noncontinuing couples showed a decrease in the correlation between the love that members reported, this was offset in continuing daters by increasingly similar reports of reward, equity, and liking. Results are discussed in terms of initial versus gradually evolving differences between continuing and noncontinuing relationships.     

Inmates' perceptions of determinate and indeterminate sentences

The movement to replace indeterminate with determinate sentencing is among the most important recent developments in the criminal justice field. While the views of citizens and scholars on the subject have been widely promulgated, little is known about those of the ultimate “consumers” of sentencing reform, namely, inmates. This article examines the views of a systematic sample of inmates in a maximum security institution in Massachusetts. Subjects' opinions were sought on the relative merits of the two typs of sentencing, and possible behavioral and deterrent effects of a proposed switch to determinate sentencing. More inmates were found to be either opposed to or undecided about than in favor of determinate sentencing.     

EFFECTS OF PICTURE PROMPTS ON THE ACQUISITION OF COMPLEX VOCATIONAL TASKS BY MENTALLY RETARDED ADOLESCENTS

The effects of using picture prompts on the acquisition, generalization, and maintenance of complex vocational tasks were evaluated within a multiple baseline design across subjects and tasks. Five moderately and severely mentally retarded adolescents were first trained to use picture prompts to guide their performance on one or more complex tasks. Following training, posttesting with and without the picture prompts was conducted to evaluate the effects of training and to determine maintenance effects over a 2- to 4-week interval. Generalization of performance across tasks was assessed with three of the students who were provided novel tasks (with and without picture prompts) without training. Results indicated that picture prompts can be successfully used to promote both acquisition and generalization of performance, and that subsequent training time on a novel task was reduced when the use of picture prompts had been previously trained.     

Cardiac orienting responses of 6- and 16-week-old infants

Since previous data suggested that the magnitude of orienting evidenced by cardiac deceleration increased over the first 16 weeks of life, 6- and 16-week-old infants were compared on various characteristics of orienting: habituation, dishabituation, and magnitude of deceleration to stimulus offset as well as to stimulus onset. Neither the change in stimulus following habituation trials nor the stimulus offset produced a large enough response to confidently evaluate age differences suggested by the data. Stimulus onset elicited a pronounced deceleration which for the two age groups was of equivalent magnitude on initial trials and declined similarly with stimulus repetition. It was suggested that similarity of the two age groups on these parameters was due to control of state within a narrow alert range, and that, in general, younger infants are less likely than older infants to show orienting when conditions for orienting are marginal.     

Frequency recognition in temporal interference tasks: A comparison among four psychophysical procedures

The frequency discrimination of a 20-msec test tone was measured for the same subjects in four psychophysical paradigms: a single-interval procedure, a two-alternative forced-choice procedure, a same-different procedure, and a method-of-adjustment procedure. In each paradigm, the 20-msec test tone was preceded or followed by a 500-msec, 800-Hz interfering tone. The interfering tone occurred 50 or 5 msec before the onset of the test tone (forward interference) or 100 or 5 msec after the offset of the test tone (backward interference). In each of the four paradigms and for each of the interference conditions the value of Δf for the test tone was varied symetrically around 800 Hz to obtain an estimate of the frequency discrimination thresholds. In all psychophysical paradigms except for the single-interval procedure, there were small or no significant differences in observers’ frequency discrimination behavior among the interference conditions. The thresholds for Δf from these conditions were approximately the same as those obtained without an interfering tone. In the single-interval task, when the test tone preceded the interfering tone (backward interference) by 5 msec, an increase in the value of Δf required for discrimination over that required in the other conditions was measured. These results suggest that the effect of backward interference on a target tone does depend on psychophysical procedure.     

The relationship between aerobic activity and cognitive performance under stress

This study examined the relationship between regular aerobic activity and cognitive performance under stress when personality and inherent aptitude were statistically controlled. Aerobically conditioned subjects have been shown to mediate the physiological response to stress under physical challenge. Would aerobically conditioned subjects also respond more efficiently to psychological stress under cognitive challenge? Forty volunteers completed a battery of personality and aptitude measures and then completed two cognitive tasks (written tests of logic), one under a condition of no stress, the other while being verbally pressured by a test monitor. Heart rate and blood pressure were measured during and after each cognitive task. Contrary to the experimental hypothesis, aerobic activity was related to inferior cognitive performance and to elevated blood pressure under stress. Inherent cognitive aptitude and personality traits emerged as far more important correlates of cognitive performance under stress than did the level of exercise.     

SUPPORTED EMPLOYMENT AS AN INTERVENTION PACKAGE: A PRELIMINARY ANALYSIS OF FUNCTIONAL VARIABLES

In this two-experiment investigation, the long-term (at least 6 months) employment of 51 moderately mentally retarded clients who were placed into 64 supported employment positions was first evaluated relative to 10 training and posttraining components that comprised a supported employment training package. In Experiment 1, chi-square analyses were used to identify three components that differentiated successful (employed for at least 6 months) from unsuccessful clients. In Experiment 2, 4 successful clients were further evaluated in a nonconcurrent multiple baseline design to determine whether the three variables identified during the group analysis (client advocate, collateral behavior, and follow-up plan) were included in the training packages. These results are discussed in terms of the need to establish better the functional variables of supported employment training programs.     

Temporal masking level differences for transients: Further evidence for a short-term integrator

Studies of binaural perception have indicated that subjects are able to use temporal information available in high-frequency regions of the spectrum to lateralize high-frequency waveforms but not to detect these waveforms in masking noise. The present experiments demonstrate that although high-frequency interaural difference cues are relatively ineffective in simultaneous and forward masking, they can be utilized in backward masking. In Experiment 1, large maskinglevel differences were found in backward masking for high-frequency transients presented either monaurally or with an interaural temporal delay. Experiments 2–4 examined fringe masking, effects of masker duration, and combined forward-backward masking for both high- and lowfrequency transients presented with interaural differences in phase and intensity. The results are interpreted as support for the view that the auditory system is organized into parallel shortand long-term integration systems specialized for processing transient and sustained aspects of acoustic stimulation. It is suggested that information from the two integrators is combined when analysis of interaural differences within each of the systems yields similar estimates of spatial location.