Denis J. Glencross

Information Processing Deficits In Clumsy Children

Abstract Abnormal clumsiness was investigated within the Framework of an information processing model using chronometric techniques. Eight clumsy and eight normal children were tested in two experiments in which between-group comparisons were made of the functioning of the perceptual and response selection processes. The processing of both proprioceptive and visual stimulus information was investigated. Clumsy children were found to process proprioceptive information more slowly than do normal children. However, in this modality, neither the perceptual nor response selection processes were effectively manipulated. By comparison, no difference in the rate of processing of visual information was found. In this modality both processes were effectively manipulated and groups were not differentially affected. Thus, the findings suggest that abnormal clumsiness is associated with an information processing dysfunction which is specific to the proprioceptive modality. Moreover, the findings suggest that clumsines...

Response Complexity and the Latency of Different Movement Patterns

Two series of experiments are described in which RT of responses of varying complexity is investigated. Complexity of arm movements was manipulated in terms of (a) the amount of force exerted in resisted movements, (b) the distance moved by the limb and the direction of movement, using reversing or continuing movements, and (c) the combining of the arms in reversing and continuing movements. Simple and two-choice RT situations were used. As response complexity increased in terms of the number of sets of response units that have to be organized into a spatio-temporal sequence, the latency correspondingly increased. However latency was not affected by changes in the amount of force exerted, or in simple reversal movements. The implications of these results are discussed.

Developmental differences in a coincident timing task under speed and time constraints

Abstract The present study examines the effects of speed constraints (target velocity) and time constraints (target duration) on performance on a coincident timing task by 5-, 7- and 9-year-old children and adults. The results showed that the young children significantly improved their performance (per cent of hits) and response accuracy CE, |CE| when given longer time to perform the task. The adults were just as successful for both durations. All subjects showed better performance (per cent of hits) with slower targets, however, for the children this effect was only noticeable with targets of long duration. Target duration also revealed development changes in response control and execution, with the younger children producing different response patterns for IRT, MT and IP measures. The developmental differences at this task are discussed in terms of the control mechanisms involved and the use of strategies in responding.

The Planning of Precision Movements

Two experiments are reported in which subjects were required to make rapid aiming movements to targets of various sizes. Probe reaction time (RT) procedures were used to investigate the preparation of the response to the target. It was proposed that if the precision of movement was planned in advance, this would be reflected by the lengthening of RTs to probes presented during the latency phase of the response. The more precise the movement (to smaller targets) the longer will be the delays to the probes. The results generally supported the prediction and the probe RTs were correlated with target size. There was also some evidence that the probe was lengthening during the movement and in the region of the target.

The double step analysis of rapid manual aiming movements

The present paper examines the control principles underlying rapid manual tracking responses to horizontal double-step stimuli. The paper reports an experiment concerned with responses made to step-stimuli presented in quick succession. The amplitude of the second-step was varied between the initial step-position and the home-base. Double-step response parameters were analysed as a function of the determinant time interval (D) between the second step and the onset of the initial response. The initial response amplitude was observed to vary as a function of D. Amplitude transition functions were constructed representing the transition of the initial response amplitude between the two step positions; their slopes, furthermore, depended on the amplitude of the second target step. No delays in the initial reaction time with the interstimulus interval were observed. Minor delays to the onset of a corrective response were observed. These delays were in part related to a movement time constraint that is independent of any limitations in central processing capacity. The present findings for the manual control system are compared to double-step tracking analyses of the oculomotor control system.

34 Levels and Strategies of Response Organization

It is proposed that response organization involves a generative or construction process involving the transfer of control between a number of levels of representation (general abstraction, elemental response units, parameters). In these terms response organization and production is described as involving four formats (i) sensory guidance and control (ii) advance planning and programming (iii) presetting and tuning (iv) amendment procedures. Finally, organizational formats and strategies are discussed in relation to contextual demands and the optimization of performance.

The effects of Familial Sinistrality and preferred hand on dichaptic and dichotic tasks

Abstract Processing asymmetries for tactile-spatial and auditory-verbal processing were investigated in two studies using the S. F. Witelson (1974, Cortex, 10, 3–17) dichaptic procedure. Experiment 1 used eight right-handed males in a free recall procedure. More shapes were correctly detected by the left hand but only with a right hand response. In Experiment 2, right and left handers with no Familial Sinistrality (FS) were compared with left handers with various types of FS, looking at pre- and postcued order of report and precuing the response hand. No group showed hand asymmetry with pre- or postcuing for either responding hand. Right handers showed no difference with order of report; however, left handers made fewer correct detections for items to be reported second. There were differences between the Parental FS and the Sibling FS groups both on the dichotic listening and the haptic tasks.

Processing of proprioceptive information in Parkinson's disease patients

Abstract The present study is concerned with a comparison of Parkinsons disease patients and normal subjects on a number of simple and choice reaction time tasks in accordance with Sternbergs interactive procedures. The results indicated that the motor disorder in Parkinsons disease was at the level of output processing and related to the inability of central mechanisms to select and organize responses. Further, the results suggested that patients had difficulty in formulating complex plans or programmes for action.

Effector organization and "gradation" of effort.

It is proposed that an aspect of the effector organization process is the gradation of the response. Gradation was investigated in a hand cranking task by using strain-gauge and electromyographic recording techniques. Criteria of gradation were related to (a) the impulsive force at a particular point in the cycle of movement, (b) an index of the work done per unit of time, (c) the degree of muscle activity in each of the 6 muscles analyzed, and (d) an index of muscle activity based on the pen deflection of an EMG record. Further, two criteria of the organization of the force were employed - the force range and the consistency of the force range. None of the criteria of gradation was closely related to speed of performance, but the organizational criteria showed a trend toward being related to speed. The implications of these findings are discussed.

The relationship of target and response complexity in coincident timing performance.

This paper reports two experiments concerned with the interaction of response and target factors in a coincident timing situation. Coincident timing involves executing a response to intercept a moving target. The target response relationship was manipulated in the first experiment by providing some targets with no structure (linear path) and others containing 1 and 2 bounce points. In the second experiment, responses required 0, 1, or 2 reversals in direction. The results provide tentative support for the notion that structure in the target path could be linked to the key temporal response dynamics for improved performance consistency, and that subjects may alter their response structure to incorporate this linkage. This can be further extended to the advantage of simply moving while perceiving movement. This paper stresses the importance of examining the perceptual and motor requirements of the coincident timing skill in unison.