Posture-movement responses to stance perturbations and upper limb fatigue during a repetitive pointing task

Localized muscle fatigue and postural perturbation have separately been shown to alter whole-body movement but little is known about how humans respond when subjected to both factors combined. Here we sought to quantify the kinematics of postural control and repetitive upper limb movement during standing surface perturbations and in the presence of fatigue. Subjects stood on a motion-based platform and repetitively reached between two shoulder-height targets until noticeably fatigued (rating of perceived exertion = 8/10). Every minute, subjects experienced a posterior and an anterior platform translation while reaching to the distal target. Outcomes were compared prior to and with fatigue (first vs. final minute data). When fatigued, regardless of the perturbation condition, subjects decreased their shoulder abduction and increased contralateral trunk flexion, a strategy that may relieve the load on the fatiguing upper limb musculature. During perturbations, kinematic adaptations emerged across the trunk and arm to preserve task performance. In contrast to our expectation, the kinematic response to the perturbations did not alter in the presence of fatigue. Kinematic adaptations in response to the perturbation predominantly occurred in the direction of the reach whereas fatigue adaptations occurred orthogonal to the reach. These findings suggest that during repetitive reaching, fatigue and postural perturbation compensations organize so as to minimize interaction with each other and preserve the global task characteristics of endpoint motion.     

Perceived Responder Legitimacy and Group Identification Predict Cooperation and Compliance in a Mass Decontamination Field Exercise

Emergency responders' failure to communicate effectively during decontamination following a chemical or biological incident has been associated with increased public anxiety and reduced public compliance. In this study we applied the social identity approach to evaluating a field exercise that involved mass decontamination. Questionnaires were collected from 115 volunteers, who participated in the exercise as simulated casualties. Volunteers' perceptions of effective responder communication predicted increased self-reported compliance with decontamination, mediated by perceived responder legitimacy and identification with other group members. Developing effective communication strategies using a social psychology perspective could improve the way in which incidents are managed.     

The Utility of the State Space Grid Method for Studying Peer Interactions in Youth Sport

Although previous studies indicate that peer interactions represent an important component of the youth sport experience, studies examining peer interactions in the sport context are limited. Furthermore, the methodological tools commonly used to investigate peer interactions have restricted researchers’ understandings of the complex, reciprocal nature of these experiences. This paper outlines the potential contribution of a novel dynamic systems-based methodology, the state space grid method (SSG; Lewis, Lamey, & Douglas, 1999 Lewis, M. D., Lamey, A. V. and Douglas, L. 1999. A new dynamic system method for the analysis of early socioemotional development. Developmental Science, 2: 457–475. [Crossref], [Web of Science ®] , [Google Scholar]), to the study of peer interactions in sport. Concrete recommendations to guide the practical application of the SSG method to future peer research in youth sport are presented.     

Multimodal Perception of Reachability Expressed Through Locomotion

We investigated the information that supports perception of whether an object is within reach using a locomotor task. Participants adjusted their own position relative to a fixed target by stepping or by propelling a wheelchair until they judged it to be within reach. The to-be-reached object was presented in virtual reality. The display of the target was driven in real time as a function of the observer's movement, thus depicting a stationary virtual object at a definite distance only through the relation across optical and nonoptical patterns of stimulation. We asked participants to judge the distance they could reach with their unaided hand or when holding a rod that extended their effective reach. They could see neither their body nor the rod thereby limiting available visual information about “reachability.” As expected, our results showed that despite the limited information that was available, participants' locomotor adjustments were influenced by (a) their simulated distance from the target, (b) their arm length, and (c) the presence or absence of the rod. The type of motion (stepping or wheelchair) had little influence. However, judgment accuracy was influenced by participants' initial simulated distance from the target. We compare the performance obtained in our locomotor judgment task with previous studies that have used different methods for measuring perceived reaching-ability. We discuss perceptual information that could have supported performance within the framework of the global array.     

Implementation of Parent Management Training—Oregon Model (PMTOTM) in Iceland: Building Sustained Fidelity

Bringing empirically supported treatments (ESTs) into community settings is a challenge because of threats to therapy adherence. The nationwide implementation of Parent Management Training—the Oregon Model (PMTO) in Iceland was studied by comparing therapists' competent adherence to PMTO across three generations of therapists. To assess therapists' competence and adherence to the PMTO method, the Fidelity of Implementation Rating System (FIMP) was used as the measuring device. Of 16 therapists across three generations who entered training, 12 completed with certification. As expected, each of the three generations obtained adequate FIMP scores. Generations 1 and 3 showed equivalent levels of performance on FIMP scores at certification. A small drop in FIMP scores for Generation 2 was explained in terms of translating and culturally adjusting materials and strengthening training procedures. Results are parallel to earlier findings from the nationwide PMTO implementation in Norway and support the idea that PMTO can be implemented in community settings with high fidelity even when resources are scarce.     

Evaluation of executive functions in children and adolescents with familial Mediterranean fever

The aim of the present study was to investigate neuropsychological test performance in children and adolescents with familial Mediterranean fever (FMF). A total of 88 children and adolescents aged 8 to 17 years were included, 52 with FMF and 36 healthy controls. After the participants were administered the Children Depression Inventory (CDI) and the Screen for Child Anxiety Related Emotional Disorders (SCARED), they completed the battery tests of the Central Nervous System Vital Signs (CNSVS), a neurocognitive test battery, via computer. The battery calculates seven domain scores (Memory, Psychomotor Speed, Processing Speed, Reaction Time, Complex Attention, Executive Function, and Cognitive Flexibility) and a summary score (Neurocognition Index [NCI]). A statistically significant difference between the FMF and control groups was found in six out of seven domains, where the scores of the participants with FMF were found to be significantly lower than those of the control participants (p < .05). Although the mean Reaction Time score of the participants with FMF was found to be lower than that of the control participants, the finding was not statistically significant (p > .05). The mean CDI and SCARED scores of the participants with FMF were found to be significantly higher than those of the control participants (p < .05). Low scores in the Processing Speed and Psychomotor Speed domains of the CNSVS were significantly correlated with higher SCARED scores (r = ?.37, p = .01). Impaired cognitive functions should be taken into consideration in children and adolescents with FMF when assessing and managing this population.     

Inhibition and shifting capacities mediate adults' age-related differences in strategy selection and repertoire

Young and older adults differ in how many strategies they use to accomplish cognitive tasks. They also differ in how often they select the best strategy on each problem. Two experiments were run to determine whether two executive functions—inhibition and shifting capacities—mediate age-related differences in strategy repertoire and in strategy selection. Both experiments were run in arithmetic problem solving. In Experiment 1, young and older adults’ strategy repertoire was assessed on a problem-by-problem basis while participants solved two-digit addition problems (e.g., 42 + 76). In Experiment 2, young and older participants had to select the best strategy on each problem to find estimates of two-digit multiplication problems (e.g., 43 × 72). In both experiments, individuals’ inhibition and shifting capacities were assessed with the Trail Making Test and the Stroop Test. The main results showed that (a) older adults used a smaller strategy repertoire (Expt. 1) and selected the best strategy on each problem less frequently (Expt. 2) than young adults, (b) inhibition and shifting capacities mediated age-related differences in strategy repertoire and strategy selection, and unique age effects were no longer significant in strategy repertoire but were still significant in strategy selection after statistical control of inhibition and shifting capacities. We discuss important implications of these findings to further our understanding of strategic variations during cognitive aging.     

Mutual support in games: Some properties of Berge equilibria

The Berge equilibrium concept formalizes mutual support among players motivated by the altruistic social value orientation in games. We prove some basic results for Berge equilibria and their relations to Nash equilibria, and we provide a straightforward method for finding Berge equilibria in n-player games. We explore some specific examples, and we explain how the Berge equilibrium provides a compelling model of cooperation in social dilemmas. We show that the Berge equilibrium also explains coordination in some common interest games and is partially successful in explaining the payoff dominance phenomenon, and we comment that the theory of team reasoning provides alternative solutions to these problems.     

Social power facilitates the effect of prosocial orientation on empathic accuracy

Power increases the tendency to behave in a goal-congruent fashion. Guided by this theoretical notion, we hypothesized that elevated power would strengthen the positive association between prosocial orientation and empathic accuracy. In 3 studies with university and adult samples, prosocial orientation was more strongly associated with empathic accuracy when distinct forms of power were high than when power was low. In Study 1, a physiological indicator of prosocial orientation, respiratory sinus arrhythmia, exhibited a stronger positive association with empathic accuracy in a face-to-face interaction among dispositionally high-power individuals. In Study 2, experimentally induced prosocial orientation increased the ability to accurately judge the emotions of a stranger but only for individuals induced to feel powerful. In Study 3, a trait measure of prosocial orientation was more strongly related to scores on a standard test of empathic accuracy among employees who occupied high-power positions within an organization. Study 3 further showed a mediated relationship between prosocial orientation and career satisfaction through empathic accuracy among employees in high-power positions but not among employees in lower power positions. Discussion concentrates upon the implications of these findings for studies of prosociality, power, and social behavior.