The Learning of Programmed- and Feedback-Based Processes Controlling the Production of a Positioning Response in Two Dimensions

Two experiments were conducted to investigate the learning of the programmed- and feedback-based processes controlling the production of a slow, self-paced positioning response in two dimensions (direction and extent) in the horizontal plane. Both experiments had two phases: an acquisition phase of 60 trials with KR, followed by a KR withdrawal phase of 20 trials. In Experiment 1, one group (N=15) had visual feedback about the ongoing movement and the other group (N=15) did not. In Experiment 2, one group (N=15) practiced initiating the response in the criterion direction and moving the criterion extent, whereas, the other group (N=15) practiced initiating the response in the criterion direction and moving randomly varied extents. The results of Experiment 1 indicated that the learning of a programmed-based process is a gradually acquired freedom from visual feedback. Experiment 2 revealed that a programmed-based process can be learned independent of a feedback-based process.     

Average KR degrades parameter learning

In the present study, the effects of average knowledge of results (KR) about a set of trials on the learning of a spatiotemporal movement pattern were examined. Participants (N = 85) practiced 3 movement patterns with the same relative and absolute timing and the same relative amplitudes but with varied absolute amplitudes. Five groups of participants practiced under 1 of the following 5 conditions: KR after every trial (100% KR); average KR after every 3rd trial (average); average KR after every trial about the last 3 trials (running-average); KR after every 3rd trial (33% KR); and KR after every trial; plus average KR after every 3rd trial (both). Although there were no differences between groups in the learning of the fundamental movement pattern (or generalized motor program), average feedback (average, running-average) clearly degraded subjects' ability to learn to properly parameterize the actions in amplitude.     

The Effect of Erroneous Knowledge of Results on Skill Acquisition when Augmented Information is Redundant

Even though it can be shown that verbal knowledge of results (KR) is redundant with sensory feedback for learning certain motor skills, such findings do not eliminate the possibility that when KR is available it influences underlying learning processes. In order to examine the function of KR more closely, two experiments were designed in which the subjects received conflicting information about their own sensory feedback and the KR presented by the experimenter. In Experiment 1, two erroneous-KR groups, a correct-KR group, and a no-KR group performed 150 practice trials on a simple anticipation timing task and then performed three no-KR retention tests of 30 trials each following intervals of 10 minutes, 1 week, and 1 month. The results supported previous findings that providing correct KR is redundant in anticipation tasks. However, learning was influenced by KR as subjects performed according to the erroneous KR information, thereby ignoring their sensory feedback even after a 1-month interval. In Experiment 2, subjects practised a more complex striking response for the anticipation task for 75 trials and then performed no-KR retention trials either immediately, or 1 day or 1 week later. One of the groups received erroneous KR after 50 practice trials with correct KR. The results confirmed and extended those from Experiment 1, as erroneous KR, even after initial practice with correct KR, influenced retention performance. These results indicate that although KR provides information that is not needed to learn anticipation timing skills, this augmented verbal information is a dominant source of information that influences underlying cognitive processes involved in learning motor skills.     

The independence of recall and recognition in motor learning

A basic tenet of both current closed-loop theories of motor learning (Adams, 1971; Schmidt, 1975) is that the generation of response specifications during learning is required for the development of recall memory. Two experiments were performed to test this tenet by attempting to demonstrate the development of recall memory in the absence of response specification production. The task in both experiments required blindfolded subjects to learn to produce a rapid, novel criterion movement on a linear positioning device. Control subjects in both experiments actively produced movements during learning with knowledge of results (KR) while experimental subjects in Experiment 1 experienced only the endpoint locations and in Experiment 2 were passively moved to the endpoint locations. Following initial KR trials, both experimental and control groups attempted to actively produce the criterion movement in the absence of KR. The results of both experiments support closed-loop theory that active practice is required to develop recall memory. There was some suggestion, however, that passive experience with sensory feedback may also aid recall memory development, contrary to the two closed-loop theories.     

Hand position as a variable determining the accuracy of aiming movements

Two experiments investigated the effect of hand position on the accuracy of short- and long-duration aiming movements in the presence and absence of visual feedback. In Experiment 1 (N = 16) short aiming movements were executed rapidly, which would require them to be predominantly programmed, whereas in Experiment 2(N = 8) these movements were performed slowly enough so that visual feedback, which implies that they were predominantly programmed. However, the long-duration, short-length movements of Experiment 2 were disrupted when visual feedback was removed, which suggests that these movements were being guided by visual feedback. Having the heel of the responding hand in contact with the target platform during the response resulted in greater accuracy than no hand contact for the short-length movements of both experiments. Taken together, these results indicated that hand contact produced greater aiming accuracy than no hand contact for both programmed- and feedback-based movements.     

Kinematic information feedback for learning a rapid arm movement

The experiments reported examine the notion that knowledge of results (KR) about the outcome of a response does not provide the necessary information for optimizing performance in many skilled activities. The effect of traditional KR was contrasted with various kinematic feedback parameters in the acquisition of a single degree of freedom response requiring the minimization of movement time. Experiment 1 showed that the presentation of discrete kinematic information feedback (peak accelaration, time to peak accelaration, and velocity at the target location) did not facilitate performance over movement-time KR. Experiment 2 revealed that presentation of a computer generated velocity-time representation of the movement as terminal information feedback improved performance over movement-time KR. This facilitation occured even without knowledge of the kinematics for optimal performance. The findings suggest that the task criterion specifies the appropriate information feedback for skill learning in that the information feedback must match the constraints imposed upon response output.     

Specificity of practice: interaction between concurrent sensory information and terminal feedback

In 2 experiments, the authors investigated a potential interaction involving the processing of concurrent feedback using design features from the specificity of practice literature and the processing of terminal feedback using a manipulation from the guidance hypothesis literature. In Experiment 1, participants produced (198 trials) flexion-extension movements to reproduce a specific pattern of displacement over time with or without vision of the limb position and with 100% or 33% knowledge of results (KR) frequency. The transfer test was performed without vision and KR. In Experiment 2, the authors assessed whether sensory information processing was modulated by the amount of practice. Participants performed 54 or 396 trials under a 100% or a 33% KR frequency with vision before being transferred to a no-vision condition without KR. Results of both experiments indicated that the Vision-33% condition suffered a larger detrimental effect of withdrawing visual information than the Vision-100% condition. Experiment 2 indicated that this detrimental effect increased with practice. These results indicated the reduction in terminal feedback prompted participants to more deeply process the concurrent visual information thus reinforcing their dependency on the visual information.     

Effects of normative feedback on motor learning are dependent on the frequency of knowledge of results

Studies on normative feedback have shown superior motor learning outcomes for individuals who believe that they are performing better than others through increased self-efficacy. Nevertheless, the effects of normative feedback were never dissociated from the knowledge of results (KR) provided to the learners which potentially interacts with self-efficacy as well. Thus, we investigated whether the effects of normative feedback on motor learning, associated with self-efficacy, would be dependent on the amount of KR provided. Fifty-six participants were randomly assigned to four experimental groups in terms of KR frequency (100% and 33%) and normative feedback (positive and negative). In the acquisition phase, all groups received the average KR of their performance at the end of each block of trials (True feedback) and a fake KR based on their own performance (but said to be from a group of participants who practiced the same task) (False Feedback). The False Feedback indicated better or worse performance of the participant in comparison to the fake group, depending on their experimental group. Retention tests were performed immediately and after 24 h from the acquisition phase. To measure self-efficacy, a questionnaire on participant's efficacy was applied before the first block, after each block of trials and before the retention tests. The results revealed superiority of positive normative feedback and 100% KR frequency, compared to negative normative feedback and 100% KR frequency in the 24h retention test. No difference was found between the groups with a frequency of 33% of KR (positive and negative). All groups increased self-efficacy during practice, but there was no difference between groups at any stage of the study. We conclude that the effects of normative feedback on motor learning are dependent on the KR frequency. However, they were not associated with self-efficacy.     

Increased Sensitivity to Changes in Visual Feedback With Practice

In recent work investigating motor learning, the focus has been on the effect of modifying feedback at different levels of learning. Results suggest that learning is specific to the practiced conditions and that this specificity increases with practice. In a replication and extension of this previous work, 3 groups (N = 30 subjects) practiced a sequential positioning movement: Controls performed 300 trials with visually presented on-line kinematic feedback, whereas the other 2 groups, low practice (LP) or high practice (HP), performed, respectively, 50 or 300 trials without feedback. Pretest and posttest sessions of 10 trials each were performed with the on-line feedback. All groups improved with practice. It was apparent that the HP group exhibited more of a performance decrement in the postest than the LP group did, suggesting that motor learning is the process of forming an increasingly specific sensorimotor representation. These results have implications for motor learning paradigms, models of motor learning, and training.     

The Role of Task Experience and Prior Knowledge for Detecting Invalid Augmented Feedback while Learning a Motor Skill

Two hypotheses were investigated. These were generated from results reported by Buekers, Magill, and Sneyers (1994) and an uncertainty account of those and other effects on skill learning of erroneous knowledge of results (KR). The first hypothesis proposes that if experienced performers have developed the capability of detecting and correcting errors, then they should not be influenced by erroneous KR in the same way as novices. The second proposes that if information about the invalid feedback is given to subjects prior to the beginning of the practice trials, then the capability for assessing feedback can be accelerated such that subjects who receive this advance information should not be misled by the erroneous KR. The first hypothesis was investigated in Experiment 1 by having subjects practise an anticipation timing task for 450 trials. One group received correct KR on all trials, and another group received no KR. Half of the subjects in each group were unexpectedly switched to erroneous KR after 400 trials. Results indicated that the erroneous KR influenced both groups during acquisition and on a retention test one minute later. However, on a retention test given one week later, only the group that had practised with no KR before being switched to erroneous KR continued to show the negative influence of the invalid KR. The second hypothesis was examined in Experiment 2 by telling subjects prior to beginning practice trials that it was possible that the KR they received would be erroneous. Results showed that this intervention strategy was effective on the no-KR retention tests only for subjects who had no-KR trials alternated with trials on which they received the erroneous KR. The results of these experiments provide evidence that uncertainty about the validity of sensory feedback increases the likelihood that subjects will be misled by invalid augmented feedback. Moreover, this uncertainty can be overcome by increased experience or by providing advance knowledge about the nature of the invalid feedback.     

Average-KR schedule benefits generalized motor program learning

The main purpose of this study was to examine the effects of average Knowledge of Results (KR) on generalized motor program learning and parameter learning. Two groups of participants (n = 15 per group) performed 80 acquisition trials of sequential timing tasks. All participants were asked to depress sequentially four keys (2, 4, 8, and 6) on the numeric pad portion of the computer keyboard with the index finger of the right hand. The author presented average feedback on timing errors based on 5-trial blocks and compared this feedback schedule with every-trial feedback. Analysis of the delayed no-feedback retention test indicated a strong advantage for the average KR compared with the every-trial condition in both generalized motor program learning and parameter learning. The current results suggest that the average KR schedule may have positive effects on generalized motor program learning and parameter learning.     

A Comparison of Two References for Using Knowledge of Performance in a Motor Task

In the present study, the learning of a task in which the goal of the movement was not isomorphic with a specific movement pattern was examined. The subjects' (N = 48) goal in the task was to be both spatially and temporally accurate in reaching 4 targets with a right arm lever movement. After each acquisition trial, the displacement profile of the movement just produced was provided to all subjects as knowledge of performance (KP). The relative effectiveness of 2 possible references, with which subjects could compare the KP, was examined. One of the references examined was knowledge of results (KR), which was provided by reporting the total absolute timing and amplitude errors from the 4 targets. The other reference examined was a criterion template (CT), which was defined as the most efficient movement pattern for reaching the 4 targets. In the feedback display, CT was superimposed on the displacement profile of the movement just produced. A factorial design, in which 2 levels of KR (KR, no KR) were crossed with 2 levels of CT (CT, no CT), produced 4 feedback conditions. After 120 acquisition trials with feedback, immediate and delayed retention tests without feedback and a reacquisition test with KR (20 trials per test) were conducted. Acquisition results indicated that KR was a better reference than CT for per-forming the timing aspect of the movement and for producing the generalized motor program (GMP) associated with the most efficient movement pattern. Delayed retention results showed that KR was also a better reference than CT for learning the most efficient GMP. The calibration strategy undertaken by subjects who were provided with KR during acquisition explains the superiority of the KR reference. The calibration strategy is compared with the pattern-matching activity that was probably undertaken by subjects who had received CT as a reference.     

Resolving a conflict between sensory feedback and knowledge of results, while learning a motor skill

In a recent study, Buekers, Magill, and Hall (1992) showed that even when verbal knowledge of results (KR) was redundant with sensory feedback, erroneous KR influenced the learning of motor skills. To determine why this occurred, we conducted two experiments. In Experiment 1, subjects performed 50 practice trials on a complex anticipation task and then performed three non-KR retention tests of 25 trials each. The results indicated that when correct KR and erroneous KR were provided alternately, subjects ignored the erroneous KR and performed according to the correct KR. Experiment 2 compared different ratios of no KR to erroneous KR. The results showed that, for low ratios (1:1 and 4:1), learning experience was similar to a condition in which erroneous KR was presented on all trials. For a higher ratio (9:1), however, learning performance was similar to performance when KR was correct on all trials or was not presented. These results are interpreted as support for the hypothesis that when two conflicting sources of information are available, the subject's degree of uncertainty about the valid source of information influences his selection of the information to guide performance.     

Motor Learning as a Function of KR Schedule and Characteristics of Task-Intrinsic Feedback

Forty participants (age range = 18–35 years) practiced 1 of 2 versions of an aiming task (with or without spring resistance). Knowledge of results (KR) was provided to them either immediately or after a delay of 2 trials. Immediate KR led to significantly more accurate performance during the 80 trials in acquisition but significantly less accurate performance on a 40-trial retention test given 24 hr after practice. In addition, the spring version of the task was performed significantly less accurately than the no-spring version on the 24-hr retention test. Most important, a significant interaction on the 24-hr retention test revealed that performance of the no-spring version of the task, when KR had been given after a 2-trial delay, was significantly more accurate than performance of the other 3 combinations of task version and KR schedule. The results suggest that KR dependency in motor skill learning is related to familiarity with task-intrinsic feedback in addition to the schedule on which KR is presented.     

Motor learning as a function of KR schedule and characteristics of task-intrinsic feedback

Forty participants (age range = 18-35 years) practiced 1 of 2 versions of an aiming task (with or without spring resistance). Knowledge of results (KR) was provided to them either immediately or after a delay of 2 trials. Immediate KR led to significantly more accurate performance during the 80 trials in acquisition but significantly less accurate performance on a 40-trial retention test given 24 hr after practice. In addition, the spring version of the task was performed significantly less accurately than the no-spring version on the 24-hr retention test. Most important, a significant interaction on the 24-hr retention test revealed that performance of the no-spring version of the task, when KR had been given after a 2-trial delay, was significantly more accurate than performance of the other 3 combinations of task version and KR schedule. The results suggest that KR dependency in motor skill learning is related to familiarity with task-intrinsic feedback in addition to the schedule on which KR is presented.     

The effect of practice on component submovements is dependent on the availability of visual feedback

Participants (N = 16) were given extensive practice (1,500 trials) on a perceptual-motor aiming task. The full-vision (FV) group practiced with vision of their response cursor, whereas the no-vision (NV) group practiced in a condition without vision. Movements were made as quickly and accurately as possible, and knowledge of results (KR) was provided. The authors tested the importance of vision early and late in practice by transferring participants to the NV condition without KR. The effects of practice differed between the two conditions. The FV group increased the speed of initial impulse to get to the target quickly, then relied on vision to make discrete error corrections. Transfer tests revealed that reliance on vision remained after extensive practice. For the NV group, practice effects were associated with a reduction in the extent to which discrete error corrections were produced.     

Augmented Kinematic Feedback for Motor Learning

Although the study of feedback about goal achievement (knowledge of results, KR) has been important for the development principles of augmented information feedback in simple skills, there is reason to question the generalizability of these findings to many common learning situations. A more appropriate type of information for skill learning appears to be augmented kinematic (or kinetic) feedback regarding the movement pattern. The experiments presented here extend recent findings about KR to a paradigm involving kinematic feedback. In Experiment 1, we examined how several kinds of temporal and spatial kinematic information supplement KR in learning. Spatial kinematic variables were more effective than temporal variables, as indicated by performance in a retention test without kinematic feedback. In Experiment 2, we manipulated the schedule of augmented kinematic feedback in a method that paralleled previous KR work. We contrasted averaged schedules of augmented feedback, in which information was given either after every trial or as averaged information after every set of five trials. On retention tests without kinematic feedback given 1 day and 1 week after acquisition, averaged schedules led to enhanced performance over an every-trial format. Together, these results begin to define the variables important in kinematic feedback, and suggest that this feedback may influence learning in ways parallel to KR.     

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.     

Motor Learning Without Knowledge of Results Through the Development of a Response Recognition Mechanism

Four experiments were conducted to investigate the ability of a response recognition mechanism, developed by presenting the sensory consequences associated with the criterion movement in the absence of actual movement recall, to produce motor learning in the absence of knowledge of results (KR). In Experiments 1 and 2, a rapid linear timing task was used (10.16 cm in 100 msec), and reduction of movement error resulted over no-KR practice trials. Experiments 3 and 4 employed a slow movement-time task (750 and 1250 msec) and a linear positioning task, respectively, and no reduction of movement error occurred over the no-KR practice trials in either experiment. The ability of the response recognition mechanism to produce motor learning in the absence of KR depended upon the extent to which feedback could be used during response production.     

Knowledge of results for motor learning: relationship between error estimation and knowledge of results frequency

The authors of the present study investigated the apparent contradiction between early and more recent views of knowledge of results (KR), the idea that how one is engaged before receiving KR may not be independent of how one uses that KR. In a 2 ×: 2 factorial design, participants (N = 64) practiced a simple force-production task and (a) were required, or not required, to estimate error about their previous response and (b) were provided KR either after every response (100%) or after every 5th response (20%) during acquisition. A no-KR retention test revealed an interaction between acquisition error estimation and KR frequencies. The group that received 100% KR and was required to error estimate during acquisition performed the best during retention. The 2 groups that received 20% KR performed less well. Finally, the group that received 100% KR and was not required to error estimate during acquisition performed the poorest during retention. One general interpretation of that pattern of results is that motor learning is an increasing function of the degree to which participants use KR to test response hypotheses (J. A. Adams, 1971; R. A. Schmidt, 1975). Practicing simple responses coupled with error estimation may embody response hypotheses that can be tested with KR, thus benefiting motor learning most under a 100% KR condition. Practicing simple responses without error estimation is less likely to embody response hypothesis, however, which may increase the probability that participants will use KR to guide upcoming responses, thus attenuating motor learning under a 100% KR condition. The authors conclude, therefore, that how one is engaged before receiving KR may not be independent of how one uses KR.