Effects of precision of knowledge of results on performance of a gross motor coincidence-anticipation task

The purpose of the investigation was to determine the effects from three knowledge of results (KR) precision levels (qualitative; 0.10 sec, 0.001 sec) on the performance of a gross motor coincidence-anticipation task where subjects performed with visual and other sense modality input. Other variables included in the analysis were sex, movement distance, and practice over three blocks of trials. Absolute error (AE), constant error (CE), variable error (VE), and E scores (E) of the subjects from two experiments (N = 90; N = 54) were analyzed with 3 x 2 x 2 x 3 ANOVAs with repeated measures on the last two factors (feedback, sex, movement distance, blocks). Consistent finding from both experiments indicated that, for this gross motor coincidence-anticipation task, the subjects performed as accurately and as consistently when they received qualitative KR as when, in addition, they received more precise KR. Subjects performed with less error on the short as opposed to the long term distance pattern. Males performed with less error on the long movement pattern than females in Experiment 1; however, the only sex difference noted in Experiment 2, when the movement distances were shortened, was that males had a more on-time CE mean score.     

Short-term rhythms in the performance of a simple motor task

Following the discovery of short-term rhythmicities In physiological processes, a study was conducted to investigate existence of similar rhythms in motor behavior. Two groups of eight subjects each were tested every 10 or 20 min respectively in the performance of a linear positioning task with augmented auditory and proprioceptive feedback, for 10 consecutive hr. Each testing sample consisted of five trials with knowledge of results (KR), followed by five trials without knowledge of results (NKR). Between tests subjects drank constant amounts of fluids and urine flow was measured. Movement accuracy in the NKR condition varied rhythmically with periodicities centered at 100 min/ cycle. No comparable rhythms were found in the KR trials or in movement time. Urine flow also varied rhythmically with similar dominant periodicities, but these rhythms were unrelated to rhythms in error. The findings are interpreted to indicate rhythmic modulations in the efficiency of short-term storage and information processing from movement execution. Significance of these results to current views of motor control is discussed.     

Experimental setting affects the performance of guppies in a numerical discrimination task

A recent study found that guppies (Poecilia reticulata) can be trained to discriminate 4 versus 5 objects, a numerical discrimination typically achieved only by some mammals and birds. In that study, guppies were required to discriminate between two patches of small objects on the bottom of the tank that they could remove to find a food reward. It is not clear whether this species possesses exceptional numerical accuracy compared with the other ectothermic vertebrates or whether its remarkable performance was due to a specific predisposition to discriminate between differences in the quality of patches while foraging. To disentangle these possibilities, we trained guppies to the same numerical discriminations with a more conventional two-choice discrimination task. Stimuli were sets of dots presented on a computer screen, and the subjects received a food reward upon approaching the set with the larger numerosity. Though the cognitive problem was identical in the two experiments, the change in the experimental setting led to a much poorer performance as most fish failed even the 2 versus 3 discrimination. In four additional experiments, we varied the duration of the decision time, the type of stimuli, the length of training, and whether correction was allowed in order to identify the factors responsible for the difference. None of these parameters succeeded in increasing the performance to the level of the previous study, although the group trained with three-dimensional stimuli learned the easiest numerical task. We suggest that the different results with the two experimental settings might be due to constraints on learning and that guppies might be prepared to accurately estimate patch quality during foraging but not to learn an abstract stimulus–reward association.     

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.     

Seeing an image of the hand affects performance on a crossmodal congruency task for sequences of events

The crossmodal congruency effect (CCE) is augmented when viewing an image of a hand compared to an object. It is unclear if this contextual effect extends to a non-spatial CCE. Here, participants discriminated the number of tactile vibrations delivered to the hand whilst ignoring visual distractors on images of their own or another’s hand or an object. The CCE was not modulated by stimulus context. Viewing one’s hand from a third person perspective increased errors relative to viewing an object (Experiment 1). Errors were reduced when viewing hands, from first or third person perspectives, with additional identity markers (Experiments 2 and 3). Our results suggest no effect of context on the non-spatial CCE and that differences in task performance between hand and object images depend on their visual properties. These findings are discussed in light of the relationship between body representation and perception of body-centred stimuli in the temporal domain.     

Stimulus-dependent modulation of perceptual and motor learning in a serial reaction time task

In two experiments, we investigated the impact of spatial attributes on the representation acquired during a serial reaction time task. Two sequences were used, in which structural regularities occurred either in the horizontal or in the vertical locations of successive stimuli. After training with the dominant hand, participants were required to respond with the non-dominant hand to either the original sequence or to a mirror-ordered version of the original sequence that required finger movements homologous to those used during training. We observed that a difference in reaction times between the two transfer conditions was smaller in the vertical sequence than in the horizontal sequence. This pattern of results was independent of whether three fingers (Experiment 1) were used or only one finger (Experiment 2) was used for responding. This result suggests that perceptual and motor learning mechanisms may be weighted differently depending on the context in which the stimulus is presented.     

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.     

Development of unimanual versus bimanual task performance in an isometric task

Sixty-three children between 5 and 12 years of age and 15 adults performed a unimanual and a bimanual isometric force task. The performance of the preferred hand in the unimanual task was compared to the performance of the preferred hand in the bimanual task. It was hypothesized that in the bimanual task the absolute error will be higher, there will be more irregularity and the participants will need more time due to the additional effort from the central nervous system, especially with respect to the communication between the hemispheres. Furthermore, in younger children bimanual force variability was expected to be higher due to developmental aspects concerning callosal maturation and attention. It was found that with respect to force generation the preferred hand was not affected by bilateral isometric force generation, but with respect to force regulation it was. The coefficient of variation (CV) of the force was 34% larger in the bimanual task as compared to the unimanual task. For the time to target force, the increase was 28%. With repetition of the trials the CV decreased in the bimanual task, but only in the youngest age group. During development there was no change in absolute error, yet there was a major reduction in force variability in the bimanual task. It is suggested that improvement in interhemispheric communication and in the ability to focus attention plays a role in the decrease in variability with age.     

Timing dysfunctions in schizophrenia as measured by a repetitive finger tapping task

Schizophrenia may be associated with a fundamental disturbance in the temporal coordination of information processing in the brain, leading to classic symptoms of schizophrenia such as thought disorder and disorganized and contextually inappropriate behavior. Although a variety of behavioral studies have provided strong evidence for perceptual timing deficits in schizophrenia, no study to date has directly examined overt temporal performance in schizophrenia using a task that differentially engages perceptual and motor-based timing processes. The present study aimed to isolate perceptual and motor-based temporal performance in individuals diagnosed with schizophrenia using a repetitive finger-tapping task that has previously been shown to differentially engage brain regions associated with perceptual and motor-related timing behavior. Thirty-two individuals with schizophrenia and 31 non-psychiatric control participants completed the repetitive finger-tapping task, which required participants to first tap in time with computer-generated tones separated by a fixed intertone interval (tone-paced tapping), after which the tones were discontinued and participants were required to continue tapping at the established pace (self-paced tapping). Participants with schizophrenia displayed significantly faster tapping rates for both tone- and self-paced portions of the task compared to the non-psychiatric group. Individuals diagnosed with schizophrenia also displayed greater tapping variability during both tone- and self-paced portions of the task. The application of a mathematical timing model further indicated that group differences were primarily attributable to increased timing – as opposed to task implementation – difficulties in the schizophrenia group, which is noteworthy given the broad range of impairments typically associated with the disorder. These findings support the contention that schizophrenia is associated with a broad range of timing difficulties, including those associated with time perception as well as time production.     

Timing dysfunctions in schizophrenia as measured by a repetitive finger tapping task

Schizophrenia may be associated with a fundamental disturbance in the temporal coordination of information processing in the brain, leading to classic symptoms of schizophrenia such as thought disorder and disorganized and contextually inappropriate behavior. Although a variety of behavioral studies have provided strong evidence for perceptual timing deficits in schizophrenia, no study to date has directly examined overt temporal performance in schizophrenia using a task that differentially engages perceptual and motor-based timing processes. The present study aimed to isolate perceptual and motor-based temporal performance in individuals diagnosed with schizophrenia using a repetitive finger-tapping task that has previously been shown to differentially engage brain regions associated with perceptual and motor-related timing behavior. Thirty-two individuals with schizophrenia and 31 non-psychiatric control participants completed the repetitive finger-tapping task, which required participants to first tap in time with computer-generated tones separated by a fixed intertone interval (tone-paced tapping), after which the tones were discontinued and participants were required to continue tapping at the established pace (self-paced tapping). Participants with schizophrenia displayed significantly faster tapping rates for both tone- and self-paced portions of the task compared to the non-psychiatric group. Individuals diagnosed with schizophrenia also displayed greater tapping variability during both tone- and self-paced portions of the task. The application of a mathematical timing model further indicated that group differences were primarily attributable to increased timing – as opposed to task implementation – difficulties in the schizophrenia group, which is noteworthy given the broad range of impairments typically associated with the disorder. These findings support the contention that schizophrenia is associated with a broad range of timing difficulties, including those associated with time perception as well as time production.     

The relationship between types of feedback, gain of a display and feedback precision in acquisition of a simple motor task

Three experiments are reported which investigate the role of concurrent and terminal feedback in the acquisition of a discrete positioning task. Experiments I and II compare the efficiency of concurrent visual feedback (CVF) and terminal visual feedback (TVF) as training methods when the gain of the visual display is varied from 1:1 to 4:1. There is a consistent interaction between feedback method and gain of the display over the recall trials. Concurrent visual feedback is inferior to terminal visual feedback at a gain of 4:1 in Experiment I and when the displayed and actual movement directions differ (Experiment II). Experiment III explores the relationship between concurrent and terminal feedback when feedback is of a digital form and its precision is varied. Concurrent feedback is worse as a training method although there is no interaction between feedback method and precision of feedback. These findings are discussed in the light of a variety of factors which could contribute to the inferiority of concurrent feedback as a training method.     

Impaired performance of right-brain-damaged patients on a sentence anagram task

A sentence anagram task was used to examine the right cerebral hemispheres's role in core grammatical functioning at the syntactic level. The test consisted of two subsets of stimuli involving empty categories: (a) those that required the empty category to be filled, and (b) those that allowed the category to remain empty. Three hypotheses were presented: (1) right-brain-damaged patients (RBDs) would be more sensitive to subset (a) than (b), (2) RBDs would perform similarly to left-brain-damaged subjects, and (3) non-brain-damaged controls would outerperform both brain-damaged groups. With all hypotheses supported, the discussion focuses on an explanation for RBDs' sensitivity to the first subset of stimuli.     

Sensory feedback in the learning of a novel motor task

The role of different forms of feedback is examined in learning a novel motor task. Five groups of ten subjects had to learn the voluntary control of the abduction of the big toe, each under a different feedback condition (proprioceptive feedback, visual feedback, EMG feedback, tactile feedback, force feedback). The task was selected for two reasons. First, in most motor learning studies subjects have to perform simple movements which present hardly any learning problem. Second, studying the learning of a new movement an provide useful information for neuromuscular reeducation, where patients often also have to learn movements for which no control strategy exists. The results show that artificial sensory feedback (EMG feedback, force feedback) is more powerful than "natural" (proprioceptive, visual, and tactile) feedback. The implications of these results for neuromuscular reeducation are discussed.     

The impact of fear words in a secondary task on complex motor performance: a dual-task climbing study

The relationship between emotion and motor action has been previously examined using relatively simple motor tasks. However, there has been limited research using more complex physical tasks. One such complex physical task is high-angle climbing. In this experiment, we examined the performance of climbers in a dual climbing and word memory task, in which they were asked to recall fear-related or neutral words after the climb, as well as single-task performance. Climbing distance, efficiency, and word recall all significantly decreased in the dual-task conditions, relative to the single tasks. Climbing distance and efficiency also decreased in the fear word dual task, relative to the neutral word memory dual task. Subjective measures of performance indicated that climbers were aware of impaired climbing performance in the dual tasks, relative to the climbing-only condition, but that they were not aware of the increased impairment caused by the fear words. These findings have important theoretical and practical implications, particularly in occupational settings requiring climbing-like operations, such as fire-fighting and search and rescue.     

Perception and action in a far-aiming task: Inhibition demands and the functionality of the Quiet Eye in motor performance

It is incontestable that high motor performance requires an optimal coupling between perception and action. In sports as well as in professional tasks, the Quiet Eye (QE) – defined as the final fixation before movement initiation – has been found to explain a considerable amount of variance in motor performance and expertise. In the current series of studies, the underlying mechanisms of this perception-action variable were further investigated by testing predictions of the inhibition hypothesis. According to the inhibition hypothesis, the functionality of the QE is to shield movement parametrization. By manipulating the demands during response selection (Experiment 1 and Experiment 2) and movement control (Experiment 2) in a far-aiming task, it was found that – in line with the predictions – QE duration increased with increasing inhibition demands. This effect was mainly driven by the similarity rather than the number of possible actions. Moreover, the relation between inhibition demands and QE-duration were sustained through both response selection and movement control, which is perfectly in line with the notion of a continuous perception-action cycle in motor behavior. In sum, these findings corroborate the inhibition function as an integral component within a cognitive understanding of the QE phenomenon.