Effects of physical fatigue and cognitive challenges on the potential for low back injury

There is no question that the motor control system will adapt under fatiguing conditions; however, there is documented evidence showing that when fatigued or challenged, the motor control system will, on occasion, perform inappropriate muscle sequencing, increasing the risk of injury, or directly causing injury. Knowing that inappropriate muscle activations can lead to injury, the purpose of this study was to investigate motor patterns during cognitive and physical challenges. Rather than ensure change with severe challenges, milder challenges were purposefully chosen. Eight male subjects performed a low external load task performed near end ROM while in an unchallenged state, and while in three challenged states: passive tissue creep, muscle fatigue and cognitive distraction. Data were collected using EMG of the trunk muscles and angular displacement of the lumbar spine. Comparison of motor control patterns between the unchallenged state and each of the three challenged conditions showed no systematic differences. However, several random anomalies were observed. A case study of a single subject was chosen to show inappropriate motor control during one trial under the cognitive distraction conditions. The response of the motor control system is very individualized and does on occasion produce inappropriate motor patterns. This supports the notion that injury may also occur as the result of random motor control errors as well as predictable, systematic changes.     

Lending a Helping Hand: The Effects of Gender Stereotypes and Gender on Likelihood of Helping1

The purpose of this study was to investigate the effects of gender and gender-role stereotypes on judgments of help-giving. As part of a 2 × 2 within-subjects design, 40 undergraduates read 4 different scenarios that described either a man or a woman needing help in either a stereotypically masculine or a stereotypically feminine situation. Although male participants felt more sympathy for men in stereotypically feminine situations and for women in stereotypically masculine situations, they were no more likely to help these individuals than they were to help those in gender-consistent situations. By contrast, women were more likely to help people in gender-inconsistent situations, despite feeling the most sympathy for people needing help in masculine situations. Implications for Weiner's (1980) attribution model of help-giving and Nadler & Fisher's (1986) threat-to-self-esteem model are discussed.     

CONTINGENT REINFORCEMENT OF ABSTINENCE WITH INDIVIDUALS ABUSING COCAINE AND MARIJUANA

Two males diagnosed with cocaine dependence received a behavioral intervention comprised of contingency management and the community reinforcement approach. During the initial phase of treatment, reinforcement was delivered contingent on submitting cocaine-free urine specimens. The community reinforcement approach involved two behavior therapy sessions each week. Almost complete cocaine abstinence was achieved, but regular marijuana use continued. During a second phase, reinforcement magnitude was reduced, but remained contingent on submitting cocaine-free specimens. Behavior therapy was reduced to once per week. Cocaine abstinence and regular marijuana use continued. Next, reinforcement was delivered contingent on submitting cocaine- and marijuana-free specimens. This modified contingency resulted in an abrupt increase in marijuana abstinence and maintenance of cocaine abstinence. One- and 5-month follow-ups indicated that cocaine abstinence continued, but marijuana smoking resumed. These results indicate that the behavioral intervention was efficacious in achieving abstinence from cocaine and marijuana; maintenance, however, was achieved for cocaine only.     

Developmental epidemiologically based preventive trials: Baseline modeling of early target behaviors and depressive symptoms

Describes a conceptual framework for identifying and targeting developmental antecedents in early childhood that have been shown in previous work to predict delinquency and violent behavior, heavy drug use, depression, and other psychiatric symptoms and possibly disorders in late adolescence and into adulthood. Criteria are described that guided choices of targets for two epidemiologically based, randomized preventive trials carried out in 19 elementary schools in the eastern half of Baltimore, involving more than 2,400 first-grade children over the course of first and second grades. Baseline models derived from the first of two cohorts show the evolving patterns of concurrence among the target antecedents. The central role of concentration problems emerged. From Fall to Spring in first grade, concentration problems led to shy and aggressive behavior and poor achievement in both genders and to depressive symptoms among girls. There was evidence for reciprocal relationships in girls. For example, depressive symptoms led to poor achievement in both girls and boys, whereas poor achievement led to depressive symptoms in girls but not boys, at least over the first-grade year. These results provide important epidemiological data relevant to the developmental paths leading to the problem outcomes and suggest preventive trials.     

Associative responding versus analogical reasoning by children

Following upon work which showed that college and high school students' analogy solutions were predictable from ratings of the relatedness of the words comprising the analogy choices, this study extended those results to children's analogy solutions. Achenbach's Children's Associative Responding Test was used as the criterion to determine (1) whether analogy solutions by children were as related to word relatedness ratings as analogy solutions were in previous subject samples, (2) whether individual differences in using associative responding versus analogical reasoning processes could enhance the predictability estimates, and (3) whether associative priming can affect analogy solutions. Two correlational studies were done, one on an American and another on a Nigerian sample. A third study was an experimental manipulation of choices on analogy items on an American sample. The results suggest that the answer to questions (1) and (3) is yes, but the answer to question (2) is no.     

Three studies on configural face processing by chimpanzees

Previous studies have demonstrated the sensitivity of chimpanzees to facial configurations. Three studies further these findings by showing this sensitivity to be specific to second-order relational properties. In humans, this type of configural processing requires prolonged experience and enables subordinate-level discriminations of many individuals. Chimpanzees showed evidence of a composite-like effect for conspecific but not human faces despite extensive experience with humans. Chimpanzee face recognition was impaired only when manipulations targeted second-order properties. Finally, face processing was impaired when individual features were blurred through pixelation. Results confirm that chimpanzee face discrimination, like humans, depends on the integrity of second-order relational properties.     

Learning errors from fiction: Difficulties in reducing reliance on fictional stories

Readers rely on fiction as a source of information, even when fiction contradicts relatively well-known facts about the world (Marsh, Meade, and Roediger, 2003). Of interest was whether readers could monitor fiction for errors, in order to reduce suggestibility. In Experiment 1, warnings about errors in fiction did not reduce students' reliance on stories. In Experiment 2, all subjects were warned before reading stories written at 6th- or 12th-grade reading levels. Even though 6th-grade stories freed resources for monitoring, suggestibility was not reduced. In Experiment 3, suggestibility was reduced but not eliminated when subjects pressed a key each time they detected an error during story reading. Readers do not appear to spontaneously monitor fiction for its veracity, but can do so if reminded on a trial-by-trial basis.     

The perception of unfamiliar faces and houses by chimpanzees: influence of rotation angle

The inversion effect, or impaired recognition of upside-down faces, is used as evidence supporting the configural processing of faces. Human studies report a linear relationship between face-discrimination performance and orientation, such that recognition is more difficult as faces are rotated away from their typical viewpoint. Previous studies on chimpanzees also support a configural bias for processing faces, particularly faces for which subjects have developed expertise. In the present study, we examined the influence of expertise and rotation angle on the visual perception of faces in chimpanzees. Six subjects were presented with unaltered and blurred conspecific faces and houses in five orientation angles. A computerized paradigm was used to further delineate the nature of configural face processing in this species. The data were consistent with those reported in humans: chimpanzees showed a significant linear impairment when discriminating conspecific faces as they rotated away from their upright orientation. No inversion effect was observed for discriminations involving houses. Thus, chimpanzees, like humans, show a face-specific inversion effect that is linearly affected by angle of orientation, suggesting that their visual processing of faces is strongly influenced by the extraction of configural cues and closely resembles the perceptual strategies of humans.