Psychometric Evidence of a Multidimensional Measure of Prosocial Behaviors for Spanish Adolescents

Prior theories and scholars rarely distinguished between distinct forms of prosocial behaviors (i.e., actions intended to benefit others) and most scholars operationalize prosocial behaviors as a global construct. Furthermore, stringent tests of psychometric properties of prosocial behavior measures are rare, especially in countries other than the United States. The present study was designed to examine the structure and functions of a multidimensional measure of prosocial behaviors in youth from Spain. Six hundred and 66 adolescents (46% girls; M age = 15.33 years, SD = 0.47 years) from Valencia, Spain, completed the Prosocial Tendencies Measure-Revised (PTM-R), measures of sympathy, perspective taking, and a global measure of prosocial behavior. Results showed that the hypothesized 6-factor structure of the PTM-R had good fit, the best fit model as compared to alternative models, and that there were several unique patterns of relations between specific forms of prosocial behaviors and sympathy, perspective taking, and the global measure of prosocial behavior. Furthermore, although there were significant gender differences in some forms of prosocial behaviors, the structure of the PTM-R was equivalent across gender. Discussion focuses on the implications for theories and measurement of prosocial behaviors.     

Interplay of Biomechanical Constraints and Kinematic Strategies in Selecting Arm Postures

In this study, the authors examined the interplay between biomechanics and control strategies in the resolution of excess degrees of freedom at the joint level. Seven participants made aimed arm movements from 30 starting points and several starting postures to targets. Final arm postures for movements to a target exhibited substantial joint angle variation. Through regression modeling and by comparing observed final arm postures with biomechanically plausible postures, the authors identified 3 kinematic strategies: (a) Maintain deviations from the average angle at the starting point to the joint's final posture; (b) make torso rotations that are a fixed proportion of shoulder rotations; and (c) adopt a characteristic combination of 4 wrist-positioning approaches. The results demonstrated that kinematic strategies can account for substantial variance in final arm postures, if one takes into account 2 types of individual differences—those that arise inevitably from biomechanical constraints and those that reflect choices in movement strategy.     

Executive Function in Young Children and Chimpanzees (Pan troglodytes): Evidence From a Nonverbal Dimensional Change Card Sort Task

In this article the authors compared chimpanzees’ executive function with that of children. They developed a nonverbal dimensional change card sorting task, which indexed the development of executive function. Three pairs of mother and offspring chimpanzees and 30 typically developed 5-year-old children were presented with 2 target stimuli and a test stimulus comprising 2 dimensions (size and shape) on a display; they were required to sort the test stimulus according to 1 dimension (e.g., shape). After 5 consecutive correct trials, the participants had to sort the test stimulus according to the other dimension (e.g., size). The results showed that the chimpanzees often failed to sort the test stimuli according to the first and reversed dimensions. On the other hand, the children were correctly able to use both dimensions. These results indicate that chimpanzees may have less developed executive skills than children.     

Center of Gravity Motions and Ankle Joint Stiffness Control in Upright Undisturbed Stance Modeled Through a Fractional Brownian Motion Framework

The authors modeled the center of gravity vertical projection (CG_V) and the difference, CP - CG_V, which, combined, constitute the center of pressure (CP) trajectory, as fractional Brownian motion in order to investigate their relative contributions and t heir spatiotemporal articulation. The results demonstrated that CG_V and CP - CG_V motions are both endowed in complementary tashion with strong stochastic and part-deterministic behaviors. In addition, if the temporal coordinates remain similar for all 3 trajectories by definition, the switch between the successive control mechanisms appears for shorter displacements for CP - CG_V and CG_V than for CP trajectories. Results deduced from both input (CG,) and muscular stiffness (CP - CG_V) thus provide insight into the way the central nervous system regulates stance control and in particular how CG and CP - CG are controlled.     

A Visual Representation and the Control of Manual Aiming Movements

Three experiments were conducted to determine if a representation of the movement environment is functional in the organization and control of limb movements, when direct visual contact with the environment is prevented. In Experiment 1, a visual rearrangement procedure was employed to show that a representation of the environment that provides inaccurate information about the spatial location of a target can disrupt manual target aiming. In Experiment 2, we demonstrated that spatial information about the position of a target can be destroyed by a visual pattern mask, supporting our claim that the representation is visual. A target-cuing procedure was used in Experiment 3 to show that representation of target position can be useful for premovement organization in a targetaiming task. Together our findings suggest that a short-lived visual representation of the movement environment may serve a useful role in the organization and control of limb movements.     

After-Contraction Phenomenon: Influences on Performance and Learning

Three experiments investigated the influence of an after-contraction phenomenon on the performance and learning of a dynamic force-production task. The after-contraction effect refers to an involuntary potentiation (induced by a sustained pre-contraction) that is thought to summate with voluntary motor commands to bias subsequent responding. The precontraction involved a brief (20 s) static contraction. The subsequent influence of the precontraction on a dynamic force-production task was assessed. Experiments 1 and 2 were aimed at demonstrating the direct impact of the precontraction intensity on the magnitude and decay of the after-contraction effect. The results indicated that as the intensity of the precontraction increased, the magnitude of the induced bias increased. In Experiment 3, the indirect influence on subsequent retention of varying the precontraction intensity during acquisition was investigated. The results indicated that the performance of subjects experiencing varying precontraction intensities during acquisition was inferior to that of subjects experiencing a constant precontraction intensity, but the performance of the varied precontraction intensities group was superior on the test of retention. It is noted that the paradoxical reversal from acquisition to retention is similar to that found in contextual interference experiments and may arise from similar mechanisms.     

The Effect of Rest Following Massed Practice of Continuous and Discrete Motor Tasks

Theories of the rest-related phenomena of reminiscence and warm-up decrement regard them as independent, being due to different factors. In this study it was found that rest following massed practice of a continuous task increased performance (reminiscence) and rest following massed practice of a discrete task lowered performance (warm-up decrement). The near-zero correlation found between the phenomena indicates that they are indeed independent and task-specific. Implications of the findings for the prediction of the effect of rest, and the fact that much motor learning and performance is task-specific, is discussed.     

Influence of Restricted Vision and Knee Joint Range of Motion on Gait Properties During Level Walking and Stair Ascent and Descent

Because elderly individuals experience marked declines in various physical functions (e.g., vision, joint function) simultaneously, it is difficult to clarify the individual effects of these functional declines on walking. However, by imposing vision and joint function restrictions on young men, the effects of these functional declines on walking can be clarified. The authors aimed to determine the effect of restricted vision and range of motion (ROM) of the knee joint on gait properties while walking and ascending or descending stairs. Fifteen healthy young adults performed level walking and stair ascent and descent during control, vision restriction, and knee joint ROM restriction conditions. During level walking, walking speed and step width decreased, and double support time increased significantly with vision and knee joint ROM restrictions. Stance time, step width, and walking angle increased only with knee joint ROM restriction. Stance time, swing time, and double support time were significantly longer in level walking, stair descent, and stair ascent, in that order. The effects of vision and knee joint ROM restrictions were significantly larger than the control conditions. In conclusion, vision and knee joint ROM restrictions affect gait during level walking and stair ascent and descent. This effect is marked in stair ascent with knee joint ROM restriction.     

The Influence of National Culture on the Perceived Fairness of Grading Procedures: A Comparison of the United States and China

Although the desire to be treated fairly is a fundamental human preference, perceptions of fair treatment can be influenced by cultural beliefs and values. For this article, the author used a scenario-based experimental study to examine students' fairness perceptions of grading procedures in 2 countries with distinct national cultures, China and the United States. The results suggest that culture can influence students' perceptions of the fairness of 2 aspects of procedural justice: voice and interpersonal justice. Chinese students were more likely to value interpersonal justice (i.e., being treated with dignity and respect, and being provided with explanations of grading procedures) and perceived the lack of interpersonal justice as less fair than did U.S. participants. In contrast, U.S. students were more likely to perceive voice (i.e., the opportunity to discuss and appeal a grading decision) as fair. These findings are connected to differences in the cultural values of the United States and China.     

Children's Perception of Parental Empathy as a Precursor of Children's Empathy in Middle and Late Childhood

The present study investigated the relationship between children's self-concepts and evaluations of parent figures. The subjects were elementary school children (352 males and 280 females; Grades 5 through 10) who came from intact families, divorced families, or families in which one or both parents had died. Significant relationships were obtained between children's self-concept ratings and their evaluations of their natural father and mother for both intact and divorced families. This relationship was not significant, however, for families in which a parent had died. Furthermore, children's self-ratings were not significantly correlated with their evaluations of stepparents.