On-line versus off-line control of rapid aiming movements

Recent studies have shown the importance of visual feedback during the rapid initial phase of aiming movements for the control of direction (e.g., Bard, Paillard, Fleury, Hay, & Larue, 1990; Blouin, Teasdale, Bard, & Fleury, in press; Teasdale, Blouin, Bard, & Fleury, 1991). In most of these studies, visual feedback conditions were presented in blocked sessions. Consequently, higher-order processes (e.g., feedforward and/or learning processes), along with on-line processing of visual feedback, might have contributed to the better accuracy found when subjects had visual feedback of only the initial portion of the movements (compared with movements without visual feedback). To test this possibility, we studied subjects' performance of rapid arm movements under different types of presentation (random, precued, and blocked) of the visual feedback conditions of the trajectory (no vision, initial portion only, and vision of the entire trajectory). Directional errors were larger in the no-vision condition than in both conditions with visual feedback. There were no differences among the presentation conditions, suggesting that on-line processing of visual information contributed to the control of the arm movements.     

Awareness is necessary for extracting patterns in working memory but not for directing spatial attention

The contents of working memory (WM) have predominantly been viewed as necessarily conscious. However, recent findings suggest otherwise. Here we investigate whether visual WM can represent subliminal stimuli, such that the positions of an invisible moving object can be extrapolated or learned about in terms of their task-relevant predictive power. We presented a moving cue subliminally and measured subjects' performance on an orientation-discrimination task at the naturally anticipated location on the cue's trajectory and at variably predictable off-trajectory locations. Our data show that orientation discriminability at the on-trajectory location was not significantly different from that at a nearby off-trajectory location. However, orientation discriminability at locations near the final position of the cue was significantly better than that at distal locations. This finding suggests that a moving object can still attract attention when presented subliminally. In contrast, the dynamic trajectory of the object and its task-relevant predictive patterns may not be monitored and maintained in visual WM. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Mental extrapolation and representational momentum for complex implied motions

A sequence of static displays implying consistent motions of a pattern induces distortions in memory for the last-observed appearance of the pattern. These memory distortions suggest that there is an internal analogue to physical momentum called representational momentum. Two experiments are reported comparing performance on tasks in which observers must remember the final display with those in which they are instructed to extrapolate the implied motions out to the next step in the sequence. In each experiment, the memory shifts were highly correlated with the actual rates at which the implied motions were extrapolated. In addition, the memory shifts were larger when the mental extrapolations occurred along the same directions of implied motion each time. These findings suggest that the memory shifts depend both on the rate at which the mental extrapolations are performed and on how consistently they are performed.     

The dual role of vision in sequential aiming movements

Previous research has demonstrated that movement times to the first target in sequential aiming movements are influenced by the properties of subsequent segments. Based on this finding, it has been proposed that individual segments are not controlled independently. The purpose of the current study was to investigate the role of visual feedback in the interaction between movement segments. In contrast to past research in which participants were instructed to minimize movement time, participants were set a criterion movement time and the resulting errors and limb trajectory kinematics were examined under vision and no vision conditions. Similar to single target movements, the results indicated that vision was used within each movement segment to correct errors in the limb trajectory. In mediating the transition between segments, visual feedback from the first movement segment was used to adjust the parameters of the second segment. Hence, increases in variability that occurred from the first to the second target in the no vision condition were curtailed when visual feedback was available. These results are discussed along the lines of the movement constraint and movement integration hypotheses.     

Distributed Control in Rapid Sequential Aiming Responses

The preparation and on-line control of short, rapid sequential aiming responses were studied in 3 experiments. Participants (N = 12 in Experiments 1 and 2, and 20 in Experiment 3) produced 3-segment responses (a) within self-initiation, simple reaction time (RT), and choice RT paradigms (Experiment 1); (b) without visual feedback under self-initiation conditions (Experiment 2); and (c) with and without visual feedback under simple RT conditions (Experiment 3). In all conditions in which participants initiated movement in response to an external imperative signal, the 2nd response segment was performed consistently slower than preceding and succeeding response segments. That pattern of segmental movement times was found whether or not visual feedback was available but was not evident when participants self-initiated their responses with or without visual feedback. The findings rule out the possibility that subjects' use of visual feedback is responsible for the slowing of the 2nd response segment under RT conditions and suggest that the programming of rapid sequential aiming responses can be distributed in pre- and postinitiation intervals.     

The effect of mood and pleasant versus unpleasant information feedback on performing a motor skill

The effect of negative, positive, or neutral feedback on a rotary pursuit task as a function of the subject's depressed or elated mood was ascertained. Specifically, the self-schema hypothesis was examined. Ninety female volunteers, ranging in age from 18 to 25 years, participated. They were randomly assigned to one of eight conditions based on depressed or elated mood states, elicited by Velten's (1968) mood induction procedure, and feedback. A control group received no feedback and was not subjected to a mood inducing treatment. Baseline measures and changes in mood were determined by the Multiple Adjective Affective Checklist (MAACL). Bogus feedback was offered after all but one of the trials. The subjects' mood changed significantly during the mood-inducing treatment. For motor performance, partial support was lent to self-schema. Elated and depressed subjects performed best under positive and negative feedback, respectively. The effects, however, were temporary.     

Effects of training and visual distance on speechreading performance

The purpose of this study was to investigate the effects of training on subjects' ability to speechread sentences at varying visual distances of 3-6 ft., 6-12 ft., and 12-18 ft. 15 college women who received training obtained higher sentence speechreading scores than the 15 untrained women. The emphasis placed on kinesthetic feedback may have assisted the trained subjects' performance; however, distance up to 18 ft. did not appear to affect subjects' ability to speechread sentences, regardless of training.     

Comparisons of two measures of free-operant avoidance under two conditions of response feedback

Lever-pressing responses of 6 rats were studied under a free-operant avoidance procedure, in 6 two-hour sessions. Three of the subjects were given an added visual feedback for each response; they avoided shocks more effectively than the subjects without the feedback. Two different measures of overall performance in free-operant avoidance were applied to the results of the experiment. There was little difference between the measures: both reflected the subjects' performance equally well. Relative merits of the measures and the criteria for selecting one of them were discussed.     

Global and local control of choice behavior by cyclically varying outcome probabilities

Subjects asked to simulate decision makers in a competitive bidding situation chose repeatedly between two alternatives; reward probability varied according to a sine wave function of time for one alternative but was held constant over time for the other. Learning functions for choice probability exhibited the wavelike pattern predicted by a statistical learning model. However, on later transfer trials, when success probability was independent of subjects' choices, their choice behavior continued to follow a wavelike function rather than approaching the constant .5 level predicted by the learning model. A possible basis in memory for the transfer performance was revealed in subjects' sketches of the remembered pattern of variation in reward probabilities. It is concluded that choice performance is controlled by a mixture of local feedback, in a manner described by the learning model, and more global information encoded in an abstract memory representation, with the balance of the influence shifting toward the latter when local feedback becomes uninformative.     

Schematic and situational determinants of depressed and nondepressed students' interpretation of feedback

We examined whether depressed persons' social skill deficits contribute to their negative cognitions and whether this contribution is independent of their negative schemata. Depressed (n = 60) and nondepressed (n = 60) subjects engaged in group discussions. We assessed subjects' social competence schemata with a questionnaire and subjects' actual level of social competence in the discussion through objective ratings made by codiscussants and outside observers. We found that independently of their negative schemata, depressed subjects' social skill deficits explained a significant portion of the variance in their more negative interpretation of feedback (relative to nondepressed subjects'). This suggests that real deficits in depressed persons' performance compound the effects of their negative schemata and further contribute to their negative cognitions. We also further explored findings by Dykman et al. (1989) and Lewinsohn et al. (1980).     

Representation versus process in simplicity of serial pattern completion

This study deals with the question whether preferred extrapolations of serial patterns are determined by the extrapolation process or the representation of serial patterns. Three experiments are reported. The first deals with series of letters from the alphabet. Each series gave rise to extrapolations with varying frequencies, and we investigated how well these frequencies are predicted by the information loads, stemming from three models. The model of Klahr and Wallace (1970) is mainly concerned with the process of extrapolation. The model of Simon and Kotovsky (1963) describes both the process and the representation of extrapolated series. A third model is introduced here that exclusively deals with the representation of series. The outcome indirectly indicates that the preferred extrapolation is determined by the simplest representation of a series and not by the simplest process towards this representation. To strengthen the last conclusion two experiments are added dealing with bar graph stimuli. They are designed to experimentally disentangle representation and process complexity. In the second experiment the task was to judge the complexity of each series after having extrapolated the series. In the third experiment, subjects had to judge complexity of extrapolated series without the task to extrapolate the series. The predictions from the three models make plausible that the complexity judgments of second experiment reflect the process of extrapolation and the complexity judgments of the third experiment still reflect the representation of series. The latter results again support the assumption that the preferred extrapolation is determined by the simplest representation of a series.     

Performance and motivational deficits of helplessness: the role of motivational orientations

The present study examined the hypothesis that the effect of failure feedback in producing learned helplessness would depend on the motivational orientation of a child. Extrinsically motivated children were predicted to exhibit performance decrement following a failure experience, whereas the opposite was predicted for intrinsically motivated children. In addition, success feedback was predicted to enhance subsequent performance only for the intrinsic group. Following success, failure, or no feedback on an activity reflecting spatial skills (an incomplete picture task), subjects' performance on an activity tapping different skills (i.e., anagrams) provided by a second experimenter served as the primary measure of helplessness. Subjects' intrinsic motivation in performing the incomplete picture task, a similar task (embedded figures) and a dissimilar task (dots-to-dots) was also examined. The results supported the predictions on both performance and intrinsic motivation measures. The results are discussed in terms of implications for learned helplessness as well as cognitive evaluation theories.     

Learned helplessness deficits: Uncontrollable outcomes or perceived failure?

An experiment is described showing that learned helplessness deficits are produced by prior exposure to uncontrollable outcomes rather than perceived failure. Although the controllability manipulation did produce differences in perceived success or failure, similar differences were also induced by means of instructional feedback. These latter differences, within the controllable and uncontrollable groups, were not associated with poorer performance by subjects given failure feedback. Moreover, the instructional feedback did not influence subjects' perceptions of controllability or uncontrollability. The results confirm that helplessness deficits cannot be explained as reactions to task failure.This research was supported by Research Grant A28015473 from the Australian Research Grants Scheme.     

Augmented Feedback Presented in a Virtual Environment Accelerates Learning of a Difficult Motor Task

One can use a number of techniques (e.g., from videotaping to computer enhancement of the environment) to augment the feedback that a subject usually receives during training on a motor task. Although some forms of augmented feedback have been shown to enhance performance on isolated isometric tasks during training, when the feedback has been removed subjects have sometimes not been able to perform as well in the "real-world" task as controls. Indeed, for realistic, nonisometric motor tasks, improved skill acquisition because of augmented feedback has not been demonstrated. In the present experiments, subjects (Experiment 1, N = 42; Experiment 2, N = 21) performed with a system that was designed for teaching a difficult multijoint movement in a table tennis environment. The system was a fairly realistic computer animation of the environment and included paddles for the teacher and subject, as well as a virtual ball. Each subject attempted to learn a difficult shot by matching the pattern of movements of the expert teacher. Augmented feedback focused the attention of the subject on a minimum set of movement details that were most relevant to the task; feedback was presented in a form that required the least perceptual processing. Effectiveness of training was determined by measuring their performance in the real task. Subjects who received the virtual environment training performed significantly better than subjects who received a comparable amount of real-task practice or coaching. Kinematic analysis indicated that practice with the expert's trajectory served as a basis for performance on the real-world task and that the movements executed after training were subject-specific modifications of the expert's trajectory. Practice with this trajectory alone was not sufficient for transfer to the real task, however: When a critical component of the virtual environment was removed, subjects showed no transfer to the real task.     

Eye movements and bisection behavior in spatial neglect syndrome: representational biases induced by the segment length and spatial dislocation of the stimulus

The present study explored behavioral and eye-movement measures in unilateral neglect patients in response to online bisection task (unfilled gap line). Two different tasks supported the bisection performance, a pointing and a grasping strategy. It was explored whether these different strategies may influence subjects' behavioral and eye-movement measures in response to different segment features: segment length (from shorter to longer) and segment spatial dislocation (from right to left spatial location). Consistent spatial biases were found for both bisection responses, fixation count, and duration, as well as for the first fixation count in case of pointing task. An "extreme-left" gradient effect was suggested and discussed, with patients' behavioral and eye measures more impaired. On the contrary, the patients' performance overlaps with the controls' one in case a grasping task. The direct link of visual pointing and grasping strategy, respectively, with the two cortical ventral and dorsal pathways was adduced to explain our results.     

Examining Action Effects in the Execution of a Skilled Soccer Kick by Using Erroneous Feedback

The authors examined the role of action effects (i.e., ball trajectory) during the performance of a soccer kick. Participants were 20 expert players who kicked a ball over a height barrier toward a ground-level target. The authors occluded participants' vision of the ball trajectory after foot-to-ball contact. Participants in a 1st group received erroneous feedback from a video that showed a ball-trajectory apex approximately 75 cm lower than that of their actual kick, although the ball's landing position was unaltered. Participants in a 2nd group received correct video feedback of both the ball trajectory and the landing position. The erroneous-feedback group showed a significant bias toward higher ball trajectories than did the correct-feedback group. The authors conclude that performers at high levels of skill use the visual consequences of the action to plan and execute an action.     

Examining action effects in the execution of a skilled soccer kick by using erroneous feedback

The authors examined the role of action effects (i.e., ball trajectory) during the performance of a soccer kick. Participants were 20 expert players who kicked a ball over a height barrier toward a ground-level target. The authors occluded participants' vision of the ball trajectory after foot-to-ball contact. Participants in a 1st group received erroneous feedback from a video that showed a ball-trajectory apex approximately 75 cm lower than that of their actual kick, although the ball's landing position was unaltered. Participants in a 2nd group received correct video feedback of both the ball trajectory and the landing position. The erroneous-feedback group showed a significant bias toward higher ball trajectories than did the correct-feedback group. The authors conclude that performers at high levels of skill use the visual consequences of the action to plan and execute an action.     

Kinematic information feedback and task constraints

The experiments were designed to examine the effect of task constraints on the influence of kinematic information feedback to facilitate the acquisition of discrete arm movements. The findings of Experiments 1 and 3 revealed that when the criterion kinematic trajectory was an increasing acceleration function, the most effective control space representation for kinematic feedback (i.e. position-time; velocity-position) was the one that matched the error criterion to be minimized. Furthermore, in Experiment 1 the velocity-position feedback condition led to greater performance error than the discrete knowledge of results of movement time or integrated position-time error. Experiment 2 showed that kinematic information feedback of the movement trajectory (position-time; velocity-position) did not facilitate acquisition of a constant velocity criterion, in contrast to knowledge of results of movement time or integrated velocity-position error. Collectively the findings suggest that the interaction of task and organismic constraints dictates the nature of the information feedback required to facilitate the acquisition of skill. The augmented information available must match the degrees of freedom requiring constraint in the movement sequence.     

Job performance over time is a function of latent trajectories and previous performance

Previous literature addressing job performance over time notes that past performance can affect future performance and that individuals often have distinct latent performance trajectories. However, no research to date has modeled these 2 aspects of job performance in tandem. Drawing on previous literature, the authors note that current performance may act as performance feedback, influencing future performance directly (i.e., autoregression), and that individuals differ in their performance trajectories due to individual-difference factors (i.e., latent trajectories). The authors demonstrate an autoregressive latent trajectory (ALT) model to show how both autoregressive and latent trajectory parameters may be incorporated in modeling job performance over time. Also discussed are the implications of the ALT model for future studies examining job performance longitudinally.     

Variable-ratio schedules as variable-interval schedules with linear feedback loops.

The mathematical theory of linear systems has been used successfully to describe responding on variable-interval (VI) schedules. In the simplest extension of the theory to the variable-ratio (VR) case, VR schedules are treated as if they were VI schedules with linear feedback loops. The assumption entailed by this approach, namely, that VR and VI-plus-linear-feedback schedules are equivalent, was tested by comparing responding on the two types of schedule. Four human subjects' lever pressing produced monetary reinforcers on five VR schedules, and on five VI schedules with linear feedback loops that reproduced the feedback properties of the VR schedules. Pressing was initiated by instructions in 2 subjects, and was shaped by successive approximation in the other 2. The different methods of response initiation did not have differential effects on behavior. For each of the 4 subjects, the VR and the comparable VI-plus-linear-feedback schedules generated similar average response rates and similar response patterns. The subjects' behavior on both types of schedule was similar to that of avian and rodent species on VR schedules. These results indicate that the assumption entailed by the VI-plus-linear-feedback approach to the VR case is valid and, consequently, that the approach is worth pursuing. The results also confute interresponse-time theories of schedule performance, which require interval and ratio contingencies to produce different response rates.