The role of propulsive muscles of the shoulder during quadrupedalism in vervet monkeys (Cercopithecus aethiops): implications for neural control of locomotion in primates

In comparative anatomical studies of the shoulder, the humeral retractors are often grouped together as propulsive muscles, which are important in the propulsive stroke of the forelimb during quadrupedal locomotion. Electromyographic (EMG) analyses of these muscles in opossums, cats, and dogs in general have confirmed such conclusions. An EMG study of chimpanzee shoulder muscles during knuckle-walking found, however, that the humeral retractors are either inactive or perform a function unrelated to propulsion (Larson & Stern, 1987). This contrast in muscle recruitment patterns between chimpanzees and more "typical" mammalian quadrupeds was attributed to the derived morphology of the chimpanzee shoulder. The present study examines the activity patterns of the humeral retractors in the vervet monkey, a primate more closely resembling nonprimate mammals in its shoulder morphology. The results of this EMG analysis show that despite the significant differences in anatomy between chimpanzees and vervets, the two species display very similar muscle recruitment patterns during quadrupedalism, and there is evidence for this same pattern in other species of primates. These differences in muscle activity patterns between primates and nonprimate mammals may be related to changes in the neurological control of locomotion in primates due to the evolutionary development of manipulative abilities in the primate forelimb.     

Life after Trauma: Personality and Daily Life Experiences of Traumatized People

In this study, we explored differences in personality and daily life experiences of traumatized (n= 26) versus nontraumatized (n= 30) college students. Study participants completed a variety of personality measures as well as a 28–day experience sampling study assessing daily activities, emotions, and physical health. Although not differing on general demographics, traumatized individuals reported more trait anxiety and lower self–esteem than nontraumatized individuals. They scored higher on Neuroticism, were more introverted, and were less emotionally stable than nontraumatized participants. Traumatized individuals also reported more cognitive disturbances, emotional blunting, and interpersonal withdrawal. They did not report being more depressed, but did endorse cognitive styles associated with heightened risk for depression. Earlier age of trauma was associated with more pathological outcomes: lower self–esteem and psychological well–being, more anxiety, more pessimism, and emotional constriction of positive mood. We compare this symptom profile to that of posttraumatic stress disorder.     

Evaluation of a “mental effort” hypothesis for correlations between cortical metabolism and intelligence

Previous research indicates that low scores on the Raven's Advanced Progressive Matrices (RAPM) test are associated with increased cortical glucose utilization during problem solving. We hypothesized that previous results may reflect the neurophysiological consequences of patterns of effort requirements; that is, high-effort expenditure from lower aptitude participants (for whom the problems are hard) and low-effort expenditure from higher aptitude participants (for whom the problems are easy). In this experiment, positron emission tomography (PET) data were gathered on participants (N = 28) who solved easy and hard problems that were tailored to the participants' own ability levels, thereby eliminating aptitude group differences in effort requirements. Contrary to previous results, high aptitude was associated with high cortical glucose use. Average aptitude participants showed diminished glucose use in the hard condition. A significant Group X Condition X Hemisphere Effect was also noted, with greater right hemisphere activation in the hard condition for the high-aptitude group. These results demonstrate that the relation of cerebral glucose use and cognitive ability is sensitive to participant and task selection.     

Brief report: Effects of informational feedback on aluminum can recycling

The impact of informational feedback on the depositing of aluminum cans in recycling receptacles at a medium-sized university was investigated. Informational signs were placed over 20-recycling receptacles in three academic buildings. Each informational sign was placed at eye level, with the number of aluminum cans deposited for recycling during the previous week displayed in red digits. A 65% increase in the number of aluminum cans deposited in recycling receptacles with the informational signs was observed. Furthermore, removal of the informational signs was observed to reliably decrease the number of aluminum cans deposited. These results are discussed in the context of employing feedback to increase environmental protection behaviors.     

Experiential correlates of time alone in adolescence1

Seven hundred and fifty-three observations were collected on 25 adolescents at random times during an average week. The observations consisted of self-reports completed in response to an electronic pager. The study was aimed at the question: What is the experience of time alone like for adolescents? The results suggest a complex but consistent relationship: while aloneness is generally a negative experience, those adolescents who spend a moderate amount of time alone (about 30 percent of their waking time) tend to show better overall adjustment than adolescents who are either never alone or spend more than the optimal proportion of time alone. Alienation and average moods showed inverse linear or quadratic relationships with amount of time alone. These results are discussed in terms of the possible psycho-social functions of aloneness at the adolescent stage of the life cycle.     

Factor structure of the Tennessee Self-Concept Scale for an institutionalized, disabled population

Separate factor analyses of responses to the Tennessee Self-concept Scale using item and scale data are reported for a sample of 255 disabled veterans. A global self-satisfaction factor and several subsidiary factors roughly approximate the external dimension of the scale. The internal dimension interacts with the external one in defining several factors but does not emerge as an independent dimension. Scale data yield a self-esteem factor incorporating both external and internal scales and a self-concept conflict-integration factor. The evidence supports the external dimension more than the internal dimension. The findings are consistent with previous studies that have not validated the two-dimensional design of the scale.     

The Utility of Problem-solving Training that Emphasises Selfmanagement Principles

This study examined the usefulness of an 8-week applied problem-solving training program. Specifically, the study examined (a) whether problem-solving training that emphasised self-management principles would be useful, (b) if the effects of training would persist over time, (c) whether an individual difference variable (problem-solving appraisal) would affect training outcomes, and (d) whether the cognitive responses of the subjects during the course of training were related to their problem-solving appraisal or the change process. Results indicated that problem solving training was effective at enhancing students’ problem-solving appraisal, and that the self-report changes were maintained at a 1 year follow-up. In particular, training seemed most useful for students who initially appraised their problem solving very negatively. Finally, the results suggested that the process-oriented cognitive responses were related to students' initial problem-solving self-appraisal as well as the impact of training. Implications of the results are discussed in terms of counselling interventions, problem solving training, the interpersonal influence process, and future research.