Perceptual and motor factors in the imitation of simple temporal patterns

Summary This study investigated the relative importance of perceptual and motor factors in the imitation of simple temporal patterns. Previous research in which subjects tap out interval sequences using one finger has suggested that perceptual factors play an important role in response timing. Studies of bimanual tapping, in contrast, stress the importance of motor interactions between the two hands. In this experiment we compared the ability of subjects to tap out two-interval sequences using one finger, two fingers on one hand, and two fingers on opposite hands. The results showed almost identical performance under the three response conditions. It is suggested that the perceptual relations between intervals in a pattern were the main determinant of performance in this experiment.     

The influence of perceptual and motor factors on bimanual coordination in a polyrhythmic tapping task

Summary In this study the role of perceptual and motor factors on the motor organization (integrated versus parallel) adopted by musically skilled and unskilled subjects in a polyrhythmic tapping task was investigated. Subjects tapped a 3:2 polyrhythm to match the timing of two isochronous tone trains, one tone train for each hand. Perceptual factors were examined by the manipulation of the frequency difference between the tone trains to produce either an integrated or a streamed percept. Motor factors were examined by comparison of performance on two versions of the 3:2 polyrhythm. In one (simultaneous) version, each cycle of the polyrhythm began with a simultaneous left- and right-hand tap. In the other (shifted) version a 100-ms interval was introduced between the initial left and right taps in each cycle. Examination of the pattern of variances and covariances among intertap intervals suggested that most of the subjects in this study adopted an integrated motor organization that involved interleaving the timing of the two hands. Further analysis revealed that a serial chained model described the pattern of covariances best for the simultaneous pattern, whereas a hierarchical organization described the pattern of covariances for the shifted pattern best. The finding that performance was more accurate with integrated tones than with streamed tones provides some support for a perceptual-motor facilitation hypothesis.     

Effect of delay-interval stimuli on delayed symbolic matching to sample in the pigeon

In Experiment 1, food-deprived pigeons received delayed symbolic matching to sample training in a darkened Skinner box. Trials began with the illumination of the grain feeder lamp (no food sample), or illumination of this lamp, accompanied by the raising of the feeder tray (food sample). After a delay of a few seconds, the two side response keys were illuminated, one with red and one with green light, with positions counterbalanced over trials. Pecking the red (green) comparison produced grain reinforcement if the trial had started with food (no food); pecking red after a no-food sample or green after a food sample was not reinforced. Once matching performance was stable, four stimuli were presented during the delay interval, and their effects on matching accuracy were evaluated. Both illumination of the houselight and the center key with white geometric forms decreased matching accuracy, whereas presentation of a tone and vibration of the test chamber did not. In Experiment 2, pecking the red center key was reinforced with food according to a variable interval schedule. The effects of occasional brief presentations of the four stimuli used in the first experiment on ongoing pecking were assessed. The houselight and form disturbed key pecking, but the tone and vibration did not. Thus, stimuli that interfered with delayed matching also interfered with simple operant behavior. Implications of these results for theories of remembering are discussed.     

Practice and training in bimanual coordination tasks: strategies and constraints.

There are a number of structural constraints on the coordination of the two hands. Understanding bimanual coordination involves not only identification of these constraints but also how they can be overcome or modulated. The performance of polyrhythms has been used to examine these issues. In this article the constraints on coordination are outlined and research on the acquisition of polyrhythms is reviewed. It is suggested that the constraints on the production of multifrequency ratios are overcome by integrating the timing of the two hands. Oscillator models of coordination are then considered and a two-process model of motor timing is suggested.     

Multiple sclerosis,emotion perception and social functioning

People with multiple sclerosis (MS) can experience problems in interpreting others’ emotions from faces or voices. However, to date little is known about whether difficulties in emotion perception in MS are related to broader aspects of social functioning. Also, there are few studies reporting the effect of MS on more ecologically valid assessments of emotion perception using multimodal videos. The current study looks at (1) the effect of MS on perceiving emotions from faces, voices and multimodal videos; (2) the possible role of slowed processing and executive dysfunction in emotion perception problems in MS and (3) the relationship between emotion perception and broader social functioning in MS. 53 people with MS and 31 healthy controls completed tasks of emotion perception and cognition, and assessed their levels of social support and social participation. Participants with MS performed worse than demographically matched controls on all measures of emotion perception. Emotion perception performance was related to cognitive measures in those with MS. Also, significant associations were found between emotion perception difficulties in MS and poorer social function. In particular, people with MS who had poorer emotion perception also reported lower levels of social support from their friends, and regression analysis showed that this prediction was maintained even when disease severity and cognitive function were taken into account. These results show that problems with emotion perception in MS extend to more realistic tasks and may predict key aspects of social functioning.     

The acquisition of bimanual coordination is mediated by anisotropic coupling between the hands

The present study was designed to test two predictions from the coupled oscillator model of multifrequency coordination. First, it was predicted that multifrequency tasks that match the inherent manual asymmetry (i.e., the preferred hand assigned to the faster tempo) would be easier to learn than tasks that do not match the inherent dynamics (i.e., the non-preferred hand assigned to the faster tempo). Second, in the latter case acquisition of the multifrequency coordination would involve a reorganisation of the coupling dynamics such that the faster hand would exert a greater influence on the slower hand than vice versa. Sixteen right-handed volunteers received extensive training on a 2:1 coordination pattern involving a bimanual forearm pronation-supination task. Participants were randomly assigned to one of two groups: 1L:2R in which the preferred right hand performed the higher frequency, or 2L:1R in which the non-preferred left hand performed the higher frequency. The dynamic stability of the patterns was assessed by the ability of participants to maintain the coordination pattern as movement frequency was increased. Changes in the directional coupling between the hands was assessed by transition pathways and lead-lag relationship evident in a 1:1 anti-phase frequency-scaled coordination task performed prior to and following three practice sessions of the 2:1 task. The predicted differential stability between the multifrequency patterns was evident in the initial acquisition sessions but by the end of training the two patterns evidenced equivalent stability. Unexpectedly, for both groups the fast hand displayed greater variability in amplitude and movement frequency than the slow hand perhaps reflecting anchoring afforded to the slow hand by synchronising movement endpoints with the auditory pacing metronome. Analysis of pre- to post-training changes to the coupling dynamics in the 1:1 anti-phase task support the hypothesis that acquisition of the 2L:1R pattern involved reorganisation of the inherent dynamics.     

Human sensitivity to phase perturbations in natural images: a statistical framework

Fourier-phase information is important in determining the appearance of natural scenes, but the structure of natural-image phase spectra is highly complex and difficult to relate directly to human perceptual processes. This problem is addressed by extending previous investigations of human visual sensitivity to the randomisation and quantisation of Fourier phase in natural images. The salience of the image changes induced by these physical processes is shown to depend critically on the nature of the original phase spectrum of each image, and the processes of randomisation and quantisation are shown to be perceptually equivalent provided that they shift image phase components by the same average amount. These results are explained by assuming that the visual system is sensitive to those phase-domain image changes which also alter certain global higher-order image statistics. This assumption may be used to place constraints on the likely nature of cortical processing: mechanisms which correlate the outputs of a bank of relative-phase-sensitive units are found to be consistent with the patterns of sensitivity reported here.     

Effects of attentional prioritisation on the temporal and spatial components of an interlimb circle-drawing task

This study aimed to examine the effects of directing attention to the spatial dimension of the circle-drawing task on interlimb coordination patterns across limbs. Eighteen participants performed a circle-drawing task involving in-phase and antiphase coordination modes under upper limb, contralateral and ipsilateral limb combinations. Results indicated that (a) coordination pattern stability co-varied with central cost when attentional focus was directed to the spatial dimensions of the interlimb circle-drawing task; (b) attentional focus on the spatial components modified the inherent performance asymmetries between the limbs; (c) finally, attention to the spatial components of the interlimb circle-drawing task modulated movement trajectories and at the same time the stability of temporal coordination.     

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.     

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.