Timing goals in bimanual coordination

Phase coupling between movement trajectories has been proposed as the basic mechanism of hand coordination in the production of bimanual rhythmic movements with a 1:2 frequency ratio. Here a central temporal coupling view is proposed as an alternative. Extending previous models of two-handed synchronic and alternate-hand tapping, we hypothesized that 1:2 tapping is performed under the control of a single internal timekeeper set at the frequency required for the fast hand. The fast hand is assumed to use every signal and the slow hand every other signal of the timekeeper, to produce actions coordinated in time. The model's predictions for the variance-covariance pattern of tap timing within and across hands were tested in an experiment that required tapping with both hands with 1:1 or 1:2 frequency ratio. The finger contact on the response plate was to be short or long, according to instruction. Prolonged finger contact entailed profound modifications in the movement trajectories but failed to modify the variance-covariance pattern of the tap timing. This pattern proved to conform to predictions under both the short and the long contact conditions, thus supporting the central temporal coupling hypothesis.     

What causes the spacing effect? Some effects of repetition,duration, and spacing on memory for pictures

Three experiments examined effects of the spacing of repetitions on memory for pictures. In Experiment I, the duration of the first presentation (P(1)) was manipulated, as was P(1)-P(2) spacing. The effect of spacing on judged frequency was independent of P(1) duration. In Experiment II, pictures were given M massed presentations just prior to the P(M)-P(M+1) spacing interval. The form of the spacing curve was independent of M. Neither experiment confirmed the prediction of "overhabituation," derived from the habituation-recovery explanation of the spacing effect. In Experiment III, subjects made both duration and frequency judgments. The duration judgment results were not consistent with the notion that subjects remember multiple massed presentations as single occurrences of especially long duration. Some evidence from Experiments I and III suggests that an interrupted stimulus is recognized better than one that is not interrupted-a finding that, if replicable, would support the habituation-recovery account of the spacing effect.     

Voluntary attention and the spacing effect

Three experiments were done to test the hypothesis that the spacing effect results from a voluntary decision by the subject to pay little attention to the second presentation (P₂) of an item when it occurs shortly after the first (P¹)- In all three experiments, the spacing of repetitions was varied. In Experiment I, allocation of attention was manipulated by pairing P₂ of some pictures with a signal that indicated high payoff for later retention. In Experiment II, attention was controlled more directly by requiring the subject, in one condition, to recite words aloud. In both experiments, the dependent variable was judged frequency. In neither experiment did the effect of the attention manipulation interact with that of the spacing of repetitions. In Experiment III, the number of eye fixations given a picture was taken to be a measure of attention. The number of fixations dropped from P₁ to P₂ to P₃, but was unaffected by the spacing of repetitions. The experiments provide no support for a voluntary attention explanation of the spacing effect.     

Political Skill and Work Outcomes: A Theoretical Extension,Meta‐Analytic Investigation,and Agenda for the Future

This quantitative review explored the political skill construct and its predictive ability across a number of organizational outcomes. First, we extended the Ferris et al. meta‐theoretical framework of political skill. Next, incorporating meta‐analysis, we found political skill is positively related to self‐efficacy, job satisfaction, organizational commitment, work productivity, organizational citizenship behavior (OCB), career success, and personal reputation, and negatively related to physiological strain. Political skill was not significantly related to psychological strain or perceptions of organizational politics. Using meta‐regression and dominance analyses, political skill predicted task performance after controlling for the Big Five personality characteristics and general mental ability. In a test of indirect relationships, our results suggest that personal reputation and self‐efficacy partially mediate the political skill–task performance relationship. Finally, in a post hoc test of political skill dimensions, we found that networking ability, interpersonal influence, and apparent sincerity (but not social astuteness) predicted task performance. Our findings provide a comprehensive assessment of theory and research to date on political skill and extend theoretical foundations to stimulate new inquiry into the operation of this important construct.     

Depression Anxiety Stress Scales-21: Factor Structure and Test-Retest Invariance,and Temporal Stability and Uniqueness of Latent Factors in Older Adults

This study examined the factor structure and test-retest invariance, and temporal stability and uniqueness of the latent factors (depression, anxiety, and stress) of the Depression Anxiety Stress Scales-21 (DASS-21; Lovibond & Lovibond, 1995) in group a of 269 older adults (age ranging from 60 to 85 years) from the general community. Participants completed the DASS-21 twice, 3 months apart. Confirmatory factor analysis (CFA) of their ratings at Time 1 indicated support for the original 3-factor oblique model (factors for depression, anxiety, and stress). Additional analyses showed support for test-retest invariance for both the measurement (configural, metric and thresholds) and structural (variances and covariances) components of this model. Results also indicated temporal stability and uniqueness of the latent factors. The practical, theoretical, research and clinical implications of the findings are discussed.     

Fear and its vicissitudes

Abstract

The USA has been a changed society since 9/11: the Zeitgeist either has a background of low-level angst, or when an attack occurs or a threat is sounded, the fear peaks and comes to the foreground for a time. Perhaps nothing demonstrates the degree to which fear permeates contemporary culture more than the continual presence of the measures the USA takes to be safe: airport security, the Patriot Act, the mining of formerly private information by the government, to name but a few. Can we account for the pervasive nature of fear solely by the devastating and deadly attacks 15 years ago, unspeakably horrifying though they were? This paper will explore this omnipresent fear in contemporary American culture from a psychoanalytic perspective, and in so doing hopes to shed light on the nature of that fear, why it is so persistent despite 15 years without any sequels, and what the consequences of that fear are for the American way of life. The discussion will be rounded out by linking this pervasive fear to the violence that is endemic to our age.     

Activities of daily living in children with developmental coordination disorder: dressing, personal hygiene, and eating skills

In order to understand how age, culture, and problems in motor coordination impact the performance of activities of daily living, we used focus groups and in-depth interviews with Australian and Canadian parents to examine activities of daily living of younger (5-7 years of age) and older (8-9 years of age) children with and without DCD. By comparison with their typically developing age group, children with DCD had more difficulty with dressing, personal hygiene, and eating skills. Difficulties with postural control and fine-motor skills were reported to contribute to poorer performance of activities of daily living. As expected, competence in the performance of activities of daily living improved in the older children with and without DCD and there were few differences in the performance of daily living tasks between typical children in Australia and Canada. Overall, the motor difficulties of children with DCD had a significant impact on performance of a wide range of daily activities.     

Current status of the motor program: Revisited

The motor program is a concept that has had a major influence on theorizing in the field of motor control. However, there has been a lack of consensus as to what exactly is a motor program and its role in movement organization and execution. In 1994 Morris, Summers, Matyas, and Iansek concluded from a review of the application of the motor program concept in the field of physical therapy that continued use of the term may impede progress in the field. In this paper we examine what has happened to the motor program concept in the thirteen years since the previous evaluation. The review indicates that although the term is still being used in different ways, the theoretical existence of a motor program appears to be generally accepted by researchers in experimental psychology, movement science, and neurophysiology. The recent development of powerful brain imaging techniques may allow determination of whether the motor program should be regarded as a metaphorical or literal concept.     

Emotion and motor preparation: A transcranial magnetic stimulation study of corticospinal motor tract excitability

In the present study, we examined whether preparing motor responses under different emotional conditions alters motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation delivered to the motor cortex. Analyses revealed three findings: (1) Reaction times were expedited during exposure to unpleasant images, as compared with pleasant and neutral images; (2) force amplitude was greater during exposure to unpleasant images, as compared with pleasant and neutral images; and (3) MEPs were larger while participants viewed unpleasant images, as compared with neutral images. Hence, coupling the preparation of motor responses with the viewing of emotional images led to arousal-driven changes in corticospinal motor tract excitability, whereas movement speed and force production varied as a function of emotional valence. These findings demonstrate that the effects of emotion on the motor system manifest at varying sensitivity levels across behavioral and neurophysiological measures. Moreover, they validate the action readiness component of emotional experience by demonstrating that emotional states influence the execution of future movements but, alone, do not lead to overt movement.