Form and Variability During Sit-to-Stand Transitions: Children Versus Adults

In performing the sit-to-stand transition, young children (6- to 7-year-olds) were expected to display a movement form similar to that of adults. However, movement consistency was predicted to be poorer in children than in adults because they lack refinement of motor control processes. Kinematic analysis of 10 repetitions of the sit-to-stand movement was carried out for 6 typically developing children and 6 adults. Supporting the authors' prediction of comparable form, no differences were evident between age groups for sequence of joint onsets, proportional duration of segmental motion, or in angle-angle plots of displacement at 2 segments. In contrast, within-participant variability was found to be higher for children: Coefficients of variation for most kinematic measures were twice those seen for adults. The authors interpret the children's lack of movement consistency as a reflection of inadequate stabilization of an internal model of intersegmental dynamics. Whereas adults have attained a skill level associated with refinement of that model, children have not. Children have an additional control problem because changes in body morphology throughout childhood require ongoing updating of the internal model that controls intrinsic dynamics.     

A Test of the Adams-Creamer Decay Hypothesis for the Timing of Motor Responses

The Adams-Creamer hypothesis states that S uses the decay of proprioceptive feedback from an early portion of a movement to cue a timed response at some later time. This hypothesis was tested by creating passive left-arm movement in one group and withholding it from another, and having Ss make a right-hand response when exactly 2.0 sec. had elapsed since the end of the movement Ss with left-arm feedback had less absolute and algebraic error, and greater within-S consistency than did the no-movement control Ss and, when KR was withdrawn, Ss with left-arm movement regressed less than did Ss without the left-arm movement, which provided 2 lines of support for the decay hypothesis.     

An Analysis of Motor Coordination Components for Various Localization Tasks

Localization abilities of subjects in three perceptual-motor tasks were considered before and after an exposure to a visual distortion. During this distortion the subject observed his hand ballistically point to an invisible but audible target while either receiving or not receiving knowledge of results (KR) concerning pointing accuracy. Also, subjects either received a 1-or a 4-sec rest period between each of 30 exposure ballistic pointing actions. The pre-and postexposure tasks involved the ability of a subject to accurately point to an occluded and stationary auditory target, to point to the straight-ahead position in space, and to indicate when a moving, auditory target was perceived as being in the straight-ahead position. For these tasks, the pre-vs. postexposure localization difference scores are referred to as the negative aftereffect, the proprioceptive shift, and the auditory shift, respectively. Wilkinson’s (1971) two-component additive model (negative aftereffect= proprioceptive shift plus auditory shift) held when KR was given regardless of amount of rest between exposure pointing responses. With a 4-sec rest and no KR, the relationship between coordination components was nonadditive (negative aftereffect greater than proprioceptive shift plus auditory shift).     

To Pass or Not to Pass: A Mathematical Model for Competitive Interactions in Rugby Union

ABSTRACT. Predicting behavior has been a main challenge in human movement science. An important step within the theory of coordination dynamics is to find out the rules that govern human behavior by defining order parameters and control parameters that support mathematical models to predict the behavior of a system. Models to describe human coordination have been focused on interlimb coordination and on interpersonal coordination in affiliative tasks but not on competitive tasks. This article aims to present a formal model with two attractors to describe the interactive behavior on a 2v1 system in rugby union. Interpersonal distance and relative velocity critical values were empirically identified and were included as task constraints that define the attractor landscape. It is shown that using relative velocity as a control parameter the model offers reasonable prediction concerning the decision-making process. The model has the plasticity to adapt to other settings where interpersonal distances and relative velocities amongst system components act as significant task constraints.     

A Dual Process Account of Coarticulation in Motor Skill Acquisition

Many tasks, such as typing a password, are decomposed into a sequence of subtasks that can be accomplished in many ways. Behavior that accomplishes subtasks in ways that are influenced by the overall task is often described as “skilled” and exhibits coarticulation. Many accounts of coarticulation use search methods that are informed by representations of objectives that define skilled. While they aid in describing the strategies the nervous system may follow, they are computationally complex and may be difficult to attribute to brain structures. Here, the authors present a biologically- inspired account whereby skilled behavior is developed through 2 simple processes: (a) a corrective process that ensures that each subtask is accomplished, but does not do so skillfully and (b) a reinforcement learning process that finds better movements using trial and error search that is not informed by representations of any objectives. We implement our account as a computational model controlling a simulated two-armed kinematic “robot” that must hit a sequence of goals with its hands. Behavior displays coarticulation in terms of which hand was chosen, how the corresponding arm was used, and how the other arm was used, suggesting that the account can participate in the development of skilled behavior.     

Knowledge About Hand Shaping and Knowledge About Objects

Our two experiments investigated associations between cognitive representations of objects and hand-shape categories. Hand configurations were partitioned according to prehensility and the size of the contacting surface, resulting in the classes: pinch, poke, palm, and clench. Experiment 1 elicited object names in response to configuration-name cues, provided ratings of the relevance of each configuration to a set of objects, and probed for the functions determining such relevance. Cueing with a configuration class elicited an associated object category with substantial intersubject agreement, and vice versa. Both the object categories and the functions associated with the four hand-configuration classes differed substantially, although the same object could be associated to some extent with multiple configurations, given variations in function. Experiment 2 elicited the names of hand-configuration classes in response to unfamiliar forms, which varied systematically in depth and the size of the projecting picture-plane surface. The modal response, response time, and degree of intersubject agreement were directly related to these variables. These structural variables, however, did not adequately predict shaping responses to real objects, as ascertained from Experiment 1. The results have implications for cognitive representation of motor categories and hand shaping in response to objects.     

A Direct Study of Halo Effect

Five individuals were evaluated on a 7-point scale from strongly dislike (1) to strongly like (7). A week later the same people were rated on 16 relatively distinct traits, such as carefulness, sense of humor, fairness, and sociability. For three of the rated individuals, there were no extreme ratings on the general impression (liking) scale by raters, and the correlations between those scores and mean trait ratings were .26, .32, and .36. For the other two, there were sharp and extreme ratings on the general liking scale, and correlations between those scores and mean trait ratings were .60 and .76. This method provides a more appropriate and more meaningful index of halo effect than other methods because it is based more directly on Thorndike's (1920) original concept.     

Developing Roles and Skills in Community-Living Adults With Severe and Persistent Mental Illness

People with severe and persistent mental illness often experience a disruption in the development of social roles, and the skills within these roles. Role Development, a set of guidelines for practice, is an intervention to develop roles and skills. The purpose of this study was to continue to examine the efficacy of this intervention. Ten people attending two community mental health programs participated in evaluation and treatment based on Role Development. Quantitative pretest and posttest measures were used. Qualitative components were incorporated to get a sense of the experience involved in developing roles and skills. Quantitative results indicated statistical significance (p < .05) in the development of roles and skills. Qualitative data revealed multiple trends experienced by the participants. This study contributes to the evidenced-based knowledge regarding development of roles and skills for persons living with severe and persistent mental illness.     

Validación del Cuestionario de Conflicto Interpersonal en el Trabajo (CIT) en empleados españoles

Resumen

El presente trabajo tiene como objetivo la validación a la población española de un instrumento de medida de conflictos interpersonales en el trabajo (CIT) en sus dos dimensiones (conflicto de tareas vs. conflicto de relaciones). Para ello, realizamos dos tipos de análisis con una muestra de 209 trabajadores provenientes de diferentes organizaciones españolas. El objetivo del primero fue la confirmación de la estructura factorial del cuestionario (AFC) y la demostración de su fiabilidad. El objetivo del segundo fue demostrar la validez predictiva de ambas dimensiones. La versión en español de conflictos interpersonales en el trabajo (CIT) mostró niveles aceptables de consistencia interna. Los resultados mostraron un mejor ajuste del modelo ante la existencia de una estructura bifactorial (conflicto de tareas y conflicto de relaciones) frente a un modelo unifactorial (conflicto interpersonal general) siendo diferente la relación entre ambos tipos de conflictos y las variables consecuentes de bienestar psicológico y clima de apoyo, respectivamente. Estos hallazgos apoyan la validez de constructo y la fiabilidad de la versión en español de conflictos interpersonales en el trabajo (CIT) para evaluar los distintos tipos de conflictos en muestras de habla hispana.     

The social side of shame: approach versus withdrawal

ABSTRACT

At present, the consequences and functions of experiences of shame are not yet well understood. Whereas psychology literature typically portrays shame as being bad for social relations, motivating social avoidance and withdrawal, there are recent indications that shame can be reinterpreted as having clear social tendencies in the form of motivating approach and social affiliation. Yet, until now, no research has ever put these alternative interpretations of shame-motivated behaviours directly to the test. The present paper presents such a test by studying the extent to which shame motivates a preference for social withdrawal versus a preference for social approach. Two studies (N?=?148 and N?=?133) using different shame inductions both showed people experiencing shame to prefer to be together with others (social approach) over being alone (social withdrawal). In addition, the preference for a social situation was found to be unique for shame; it was not found for the closely related emotion of guilt. Taken together, these findings provide direct empirical support for the idea that shame can have positive interpersonal consequences.