The performance of a simple motor task with kinaesthetic sense loss

Two related studies were carried out, to test the suitability of the nerve compression block as a technique in the investigation of kinaesthesis in motor skills.

In both studies a key tapping task was used. Each experimental group was composed of six volunteer subjects. It was found that kinaesthetic sensation was eliminated after pressure had been applied for 20-25 min., but muscle power was not seriously affected at this stage of the block. The results also showed a pronounced performance decrement in the absence of kinaesthetic feedback, and that this decrement was not due to emotional or other disturbances caused by the experimental procedure. The loss of tactile sensation was also observed.     

Level of aspiration and performance of chronic psychiatric patients on a simple motor task

The level of aspiration and performance was examined for 25 male psychiatric inpatients whose mean age was 57.4 yr. and mean length of hospitalization was 23.6 yr. For a simple motor task involving flipping a plastic chip over a goal line, each patient expressed the ward and his personal pretask levels of aspiration, performed the task, and expressed his personal posttask aspiration. The expressions of both the ward and pretask levels of aspiration were less than the mean score of a nonhospitalized referent group. Both performance and posttask levels of aspiration were greater than the pretask level. More patients predicted they would perform worse than the other patients on the ward than predicted they would perform better. The patients appropriately shifted their levels of aspiration either up after success or down after failure. The results were discussed according to expectations from classical theory as well as findings with schizophrenics. Implications for further research were discussed.     

Short-term limb immobilization affects motor performance

C. Ghez, J. Gordon, and M. R Ghilardi (1995; J. Gordon, M. R Ghilardi, & C. Ghez, 1995; R. L. Sainburg, M. R Ghilardi, H. Poizner, & C. Ghez, 1995) have found that proprio-ceptive deafferentation impairs feedforward and feedback mechanisms that control reaching movements. In the present study, the authors found immobilization-induced changes in limb kinematics, including joint motion, in 32 healthy participants who performed out-and-back movements before and after 0, 6, or 12 hr of immobilization of the left arm. Control participants did not undergo the arm immobilization procedure. Immobilization for 12 hr, but not 6 hr, caused trajectories with increased hand-path areas and altered interjoint coordination. The abnormalities were smaller in amplitude but similar in quality to those reported in deafferented patients (R. L. Sainburg et al.). In addition, movement onset point significantly drifted after immobilization. Thus, short-term limb disuse can affect interjoint coordination by acting on feedforward mechanisms. These behavioral alterations are potentially related to cortical plastic changes.     

The effect of visual guidance on the acquisition of a simple motor task

Subjects were required to learn to depress a bar using concurrent visual feedback, which was removed for test. The overshooting found in test is attributed to visual dominance of the feedback traces; the way in which it occurs is not clear, since the reduction of the ratio of movement to display gain from 1:15 to 1:7.5 did not reduce overshooting. Performance improved after extended practice, but the direction of error remained positive. The results are discussed in terms of motor programming and feedback control of movement and are interpreted as evidence against Adams' (1971) two-trace theory.     

Fatigue during prolonged performance on a simple compensatory tracking task

Two basic activities are involved in radar operating, watchkeeping and target tracking. Deterioration of watchkeeping performance has been explained by a hypothesis which relates absence of sensory variation and failure to attend to one part of the display continuously (Broadbent, 1951). This paper describes a preliminary experiment to examine deterioration on a simple compensatory tracking task.

Twenty-one subjects were each tested for an uninterrupted period of two hours. They were required to keep a target correctly aligned by cranking a handwheel at a constant speed, and it was expected that failures to attend to the display would result in target deviations. Analysis of the results showed that both number of errors and mean duration of errors increased significantly in consecutive half-hour periods, and that there were large individual differences in performance.     

The relative weightings of visual and nonvisual coding in a simple motor learning task

A linear positioning task was used to examine the effects of visual and nonvisual inputs on motor learning. The experiment had three factors with two levels of each namely: sensory modality (visual-nonvisual), transfer at recall (changed-unchanged), size of movement (25.4 cm, 50.8 com). Three dependent variable were used: absolute error (AE), constant error (CE), and variable error (VE). The results suggest that visual dominance causes disruption of recall in the visual, changed conditions. No disruption of recall was found for the nonvisual condition other than in terms of CE with respect to movement sizes. The results are taken to follow Posner et al.'s (1976) theory of visual dominance, but some account of the spatial qualities of visual and kinesthetic information is needed.     

How checking breeds doubt: Reduced performance in a simple workingmemory task

A paradox of memory research is that repeated checking results in a decrease in memory certainty, memory vividness and confidence [van den Hout, M. A., & Kindt, M. (2003a). Phenomenological validity of an OCD-memory model and the remember/know distinction. Behaviour Research and Therapy, 41, 369-378; van den Hout, M. A., & Kindt, M. (2003b). Repeated checking causes memory distrust. Behaviour Research and Therapy, 41, 301-316]. Although these findings have been mainly attributed to changes in episodic long-term memory, it has been suggested [Shimamura, A. P. (2000). Toward a cognitive neuroscience of metacognition. Consciousness and Cognition, 9, 313-323] that representations in working memory could already suffer from detrimental checking. In two experiments we set out to test this hypothesis by employing a delayed-match-to-sample working memory task. Letters had to be remembered in their correct locations, a task that was designed to engage the episodic short-term buffer of working memory [Baddeley, A. D. (2000). The episodic buffer: a new component in working memory? Trends in Cognitive Sciences, 4, 417-423]. Of most importance, we introduced an intermediate distractor question that was prone to induce frustrating and unnecessary checking on trials where no correct answer was possible. Reaction times and confidence ratings on the actual memory test of these trials confirmed the success of this manipulation. Most importantly, high checkers [cf. VOCI; Thordarson, D. S., Radomsky, A. S., Rachman, S., Shafran, R, Sawchuk, C. N., & Hakstian, A. R. (2004). The Vancouver obsessional compulsive inventory (VOCI). Behaviour Research and Therapy, 42(11), 1289-1314] were less accurate than low checkers when frustrating checking was induced, especially if the experimental context actually emphasized the irrelevance of the misleading question. The clinical relevance of this result was substantiated by means of an extreme groups comparison across the two studies. The findings are discussed in the context of detrimental checking and lack of distractor inhibition as a way of weakening fragile bindings within the episodic short-term buffer of Baddeley's (2000) model. Clinical implications, limitations and future research are considered.     

Factors affecting metamotivational reversals during motor task performance

Reversal theory proposes that the individual's psychological state constantly switches between metamotivational state pairs (such as Apter's 1982 telic-paratelic pair). Three factors are thought to affect reversals: frustration, contingent event, and satiation. Only a few studies have directly investigated these factors in sports contexts, and evidence is needed to assess support for these factors. In a laboratory setting, 24 participants performed a telic and a paratelic version of a dart-throwing task for 10 min. Participants were free to change from one task version to another as they wished, and reasons for any task changes were solicited. Task changes, indicative of reversals, were observed in 11 participants, and these were reported as due to satiation or frustration but not to contingent events. These findings may inform the structure of sessions on skill development but require confirmation in actual sports contexts.     

The relationship between task difficulty and motor performance complexity

Difficult tasks are commonly equated with complex tasks across many behaviors. Motor task difficulty is traditionally defined via Fitts’ law, using evaluation criteria based on spatial movement constraints. Complexity of data is typically evaluated using non-linear computational approaches. In this project, we investigate the potential to evaluate task difficulty via behavioral (motor performance) complexity in a Fitts-type task. Use of non-linear approaches allows for inclusion of many features of motor actions that are not currently included in the Fitts-type paradigm. Our results indicate that tasks defined as more difficult (using Fitts movement IDs) are not associated with complex motor behaviors; rather, an inverse relationship exists between these two concepts. Use of non-linear techniques allowed for the detection of behavioral differences in motor performance over the entire action trajectory in the presence of action errors and among neutrally co-constrained effectors not detected using traditional Fitts’-type analyses utilizing movement time measures. Our findings indicate that task difficulty may potentially be inferred using non-linear measures, particularly in ecological situations that do not obey the Fitts-type testing paradigm. While we are optimistic regarding these initial findings, further work is needed to assess the full potential of the approach.     

Motivational determinants of motor performance: The hidden second task

Summary The present study was designed to test facilitating and debilitating effects of motivational processes on motor behavior. It was predicted that motivational processes have a more pronounced effect on motor performance when control is frequently transferred to attentional mechanisms (i. e., early in the acquisition phase). The results were consistent with this expectation. A strong motive to achieve success and pretreatment designed to enhance achievement motivation were associated with an increase in the quality of performance. A strong tendency to engage in state-oriented cognitive activities, by contrast, (e.g., thinking about the potential threat to one's selfesteem resulting from failure) was associated with poorer performance, It is concluded that experiments on motor behavior in which subjects are instructed to perform a single motor task may actually involve dual-task (or even multiple-task) performance if some part of the subjects' attentional capacity is used for task-irrelevant cognitive activities.     

Short-term retention during a simultaneous detection task

Subjects were required to perform a short-term memory task and a signal detection task, both individually and simultaneously. Memory performance was impaired only when the signals in the detection task were difficult to detect. The impairment in memory was restricted to items which appeared in the early positions of the list to be remembered. Detection performance was unaffected by the simultaneous task requirement and there was no correlation between performance on the two tasks when both were performed together. The results suggest that the difficulties Ss have when they attempt to perform several tasks at the same time may be due to limitations in the processes responsible for storing and retrieving information rather than those involved in the perceptual analysis of the incoming material.     

The effects of switching between targets on the performance of a simple motor skill

Little direct evidence has emerged regarding the influence of switching between tasks on the performance of skills studied in the motor domain. The present study reported the results of two experiments that examined the effects of task switching on a simple object projection task, which presumably emphasized processes related to response planning and execution. The experimental task required participants to gently tap a knob to make it travel along two parallel rods until it reached a specified target distance. In both experiments, participants in the repeated conditions performed a single target distance while participants in the switched conditions alternated between two target distances. Results indicated that switching between targets degraded accuracy for the two short targets (30cm, Exp. 1; 20cm, Exp. 2). Results were consistent with the preservation of parameter values [Rosenbaum, D. A., Weber, R. J., Hazelett, W. M., & Hindorff, V. (1986). The parameter remapping effect in human performance. Evidence form tongue twisters and finger fumblers. Journal of Memory and Language, 25, 710-725; Sherwood, D. E. (2007). Separate movement planning and spatial assimilation effects in sequential bimanual aiming movements. Perceptual and Motor Skills, 105, 501-513] and suggested an additional role for persisting activation in accounting for spatial assimilation and magnitude effects.     

The error power spectrum as a technique for assessing the performance of the human operator in a simple task

The measurement of performance of a human operator in a closed loop control system is considered; it is suggested that the power spectrum of the fluctuations of his tracking error (or error spectral density curve) gives a useful picture of performance and the equipment and technique for producing such a curve is described briefly.

As an example of the technique the power spectra obtained on several subjects performing a simple task with a pressure joystick are given and the implications of the shape of the curve are discussed.     

Lesions of the dorsolateral or dorsomedial striatum impair performance of a previously acquired simple discrimination task

Previous evidence has suggested a specific role for the dorsal striatum, especially the dorsolateral region of the dorsal striatum, in stimulus-response learning. In a previous study, we found an impairment in animals with dorsolateral striatal lesions on a simple discrimination task (CS+/CS-), thought to require the involvement of both stimulus-reward and stimulus-response learning. It is possible that the generally poor performance of dorsolateral lesioned animals on this experiment precluded adequate exposure to stimulus-reward pairings necessary for solving this task, and, thus, had little to do with stimulus-response learning. To test this hypothesis, the performance of animals with dorsolateral and dorsomedial striatal lesions was assessed on a previously acquired simple discrimination task. To independently assess the effects of each lesion on the performance of stimulus-reward learning, dorsolateral and dorsomedial lesioned animals were assessed on a previously acquired conditioned place preference task (CPP). In agreement with our earlier experiment, and the stimulus-response interpretation of dorsolateral striatal function, animals with dorsolateral striatal lesions were found to be impaired during post-lesion performance of the simple discrimination task, but not CPP learning. Additionally, dorsomedial lesioned animals were found to be impaired in performance of the simple discrimination task, but not on the CPP task. Possible explanations for the differences between the role of the dorsomedial striatum in acquisition and expression of the simple discrimination task are proposed.