The Scheduling of Knowledge of Results

The experiments outlined in this article were performed so that the acquisition effects of KR scheduling on no-KR retention could be determined. In Experiment 1, the group that alternated between 12 KR and 12 no-KR responses produced better retention than both the group that alternated between 6 KR and 6 no-KR responses and an all-KR group. The partial KR group that performed the best on retention also received the least number of reversals from KR to no-KR responses, however. In Experiment 2, when acquisition KR reversals ere held constant for partial KR groups, groups that received either random KR scheduling or all KR produced similar and better retention that groups who received blocked KR scheduling. These results were reconciled with KR frequency experiments by proposing that memory processes invoked by KR protocols decrease from KR frequency, to reversal, to scheduling conditions.     

Summary knowledge of results for skill acquisition: support for the guidance hypothesis

Summary knowledge of results (KR) involves the presentation KR for each of a set of trials (e.g., 10) only after the last trial in the set has been completed. Earlier, Lavery (1962) showed that, relative to providing KR after each trial, a 20-trial summary KR was detrimental to performance in a practice phase with KR present but was beneficial for a no-KR retention test. Using a relatively simple ballistic-timing task, we examined summary lengths of 1 (essentially KR after every trial), 5, 10, and 15 trials, searching for an inverted-U relationship between summary length and retention performance as predicated by a guidance hypothesis for KR. During acquisition when KR was present and being manipulated, all groups showed improvements in performance across practice, while increased summary lengths generally depressed performance. However, in a delayed no-KR retention test, there was an inverse relation between the summary length in acquisition and absolute constant error on the retention test. A guidance hypothesis is favored to explain how, relative to immediate KR, long KR summaries can provide detrimental effects in acquisition while enhancing retention performance.     

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 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.     

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.     

Average KR schedule in learning of timing: influence of length for summary knowledge of results and task complexity

This experiment investigated the influence of length for average Knowledge of Results (KR) and task complexity on learning of timing in a barrier knock-down task. Participants (30 men and 30 women) attempted to press a goal button in 1200 msec. after pressing a start button. The participant was assigned into one of six groups by two tasks (simple and complex) and three feedback groups (100% KR, Average 3, Average 5). The simple and complex tasks required a participant to knock down one or three barriers before pressing a goal button. After a pretest without KR, participants practiced 60 trials of physical practice with one of the three following groups as a practice phase: one given the result of movement time after every trial (100% KR), a second given the average movement time after every third trial (Average 3), a third given the average movement time after every fifth trial (Average 5). Participants then performed a posttest with no-KR and two retention tests, taken 10 min. and 24 hr. after the posttest without KR. Analysis gave several findings. (1) On the complex task, the absolute constant error (/CE/) and the variable error (VE) were less than those on the simple task. (2) The /CE/ and the VE of the 100% KR and the Average 3 groups were less than those of the Average 5 group in the practice phase, and the VE of the 100% KR and the Average 3 group were less than those of the Average 5 group on the retention tests. (3) In the practice phase, the /CE/ and the VE on Blocks 1 and 2 were higher than on Blocks 5 and 6. (4) On the retention tests, the /CE/ of the posttest was less than retention tests 1 and 2. And, the VE of the 100% KR and the Average 3 groups were less than that of the Average 5 group. These results suggest that the average feedback length of three trials and the given feedback information after every trial are advantageous to learning timing on this barrier knock-down task.     

Examining the Preferred Self-Controlled KR Schedules of Learners and Peers During Motor Skill Learning

In many practical situations, learners are provided with feedback in the form of knowledge of results (KR) by a peer. However, when peers provide KR is currently unknown. When given the opportunity to request KR in a self-controlled manner, some participants have reported a preference for requesting KR after good performances. Alternatively, peers may provide KR in a different fashion. Subsequently, a discrepancy between the learner's desire to receive KR and when a peer provides KR may arise. In our study, peer- and self-controlled KR schedules were compared. Participants were peers who controlled KR (PC; 8), learners with peers (P-L; 8), or learners with self-control (SC; 8). Participants in the two learning groups (P-L and SC groups) completed a serial-timing task with a goal time of 2500 ms. Absolute error data on KR and no-KR trials along with self-reports indicate that participants with self-control preferred KR after good trials and peers preferred to provide KR after both good and bad trials equally. Results from the delayed retention test indicated that peer-controlled learners were more consistent (i.e., in terms of variable error) than the self-control group.     

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.     

Relearning movements: modification of an incorrectly timed reversal movement.

The main purpose of this study was to examine if an inaccurately acquired motor response can be relearned through the provision of a limited number of correct KR trials. 26 subjects were assigned to one of three experimental groups: a no-KR group, an erroneous KR group, and a relearning group who were given correct KR after 125 trials of erroneous KR. Analysis showed a significant temporal correction of the reversal movement when the erroneous KR was replaced by valid verbal information during acquisition. This adaptation, however, was attenuated during retention, indicating that the limited number of correct KR trials did not wash out the effect of the invalid information provided during the first phase of acquisition.     

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.     

Testing specificity and guidance hypotheses by manipulating relative frequency of KR scheduling in motor skill acquisition.

This investigation tested predictions of specificity and guidance hypotheses by manipulating relative frequency of knowledge of results scheduling using a shuffleboard task. Participants were assigned to either a 100%-KR, three 50%-KR conditions (Constant, Fade, Reverse), or 00%-KR condition. Based on predictions of the specificity hypothesis, it was expected the 00%-KR condition would perform the best on a no-KR retention test. It was also expected the 100%-KR condition would perform poorly on a no-KR retention test based on predictions of the guidance hypothesis. Analysis for 55 men's and 55 women's retention did not support predictions of the specificity hypothesis and provided partial support for the guidance hypothesis.     

Emergent patterns of feedback strategies in performing a closed motor skill.

This sturdy identified self-chosen patterns of feedback usage and how they influenced accuracy and consistency in performing a closed motor skill. Learners completed 100 practice trials with 25 opportunities to receive knowledge of results (KR), the timing of which was self-chosen, followed by 25 no KR retention trials. The study identified two patterns of self-chosen KR, namely, a faded frequency pattern and a reversed faded frequency pattern. Analyses of variance indicated a significant trial block effect for accuracy in acquisition and no significant main effects or interactions associated with self-chosen patterns of KR. Quantification of regularity of KR patterns yielded correlations indicating that less regularity was associated with greater accuracy in performing the task. These results were congruent with previous research on self chosen feedback.     

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.     

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.     

Effects of reducing frequency of intrinsic knowledge of results on the learning of a motor skill

The guidance hypothesis suggests too much knowledge of results during skill acquisition can be detrimental to long-term performance. Possibly, the learner becomes dependent on augmented KR and is unable to use intrinsic feedback. This study examined this hypothesis with three groups performing a golf putting task. One group received continuous KR about ball path and final location; the other groups were deprived of specific KR on 50% or 100% of the acquisition trials. As expected, the continuous KR group performed better during acquisition, but the KR-deprived groups performed better on delayed retention trials, especially when KR was absent.     

Autonomy support and reduced feedback frequency have trivial effects on learning and performance of a golf putting task

Optimizing Performance Through Intrinsic Motivation and Attention for Learning (OPTIMAL) Theory proposes that choices of any kind support an individual's need for autonomy, motivating them to learn and perform motor skills more effectively. Notably, the authors suggest asking learners to choose when to receive feedback in order to increase autonomy. Conversely, the guidance hypothesis predicts an impact of feedback schedule independent of motivational influences. The purpose of this experiment was to compare the relative and combined effects of autonomy and feedback schedule for the acquisition of a golf putting task without vision of results. Autonomy support (autonomy support vs. yoked) and knowledge of results (KR) schedule (100%-KR vs. 50%-faded-KR) were combined in a 2 × 2 factorial design. Participants (N = 56) in the autonomy support groups were asked to choose from three colours of golf balls for each putt during 10 acquisition blocks. Yoked groups were yoked to the golf ball colour choices of their autonomy support group counterparts. Participants in the 100%-feedback schedule groups were provided x- and y-coordinate KR following every putt during acquisition, while participants in the 50%-faded groups received KR after half of their putts, with feedback frequency decreasing over acquisition blocks. All participants completed a 24-h delayed retention and transfer test without KR. The results were somewhat consistent with OPTIMAL Theory yet the effects were not statistically significant and trivially small. The results were inconsistent with the guidance hypothesis.     

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.     

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.     

Reducing Knowledge of Results about Relative versus Absolute Timing: Differential Effects on Learning

The purpose of the present experiment was to examine further earlier suggestions that a reduced relative frequency of knowledge of results (KR) can enhance the learning of generalized motor programs (GMPs) but at the same time degrade parameter learning, compared with giving KR after every trial (Wulf & Schmidt, 1989; Wulf, Schmidt, & Deubel, 1993). In contrast to these earlier studies, here KR was given separately for relative timing and absolute timing. Subjects practiced three movement patterns that required the same relative timing but different absolute movement times. KR was provided on 100% or 50% of the practice trials for relative timing or absolute timing, respectively. In retention and transfer tests, the groups that had had 50% KR about relative timing demonstrated more effective learning of the relative-timing structure, that is, GMP learning, than the groups that had had 100% KR about relative timing. The KR frequency had no effect on parameterization during retention; yet, when transfer to a task with a novel overall duration was required, the groups given 100% KR about absolute timing were more accurate in parameterization than the groups provided with 50% KR about absolute timing. Thus, the reduced relative KR frequency enhanced GMP learning but had no beneficial effect, or even a degrading effect, on parameter learning. The differential effects of a reduced KR frequency on the learning of relative timing and absolute timing also provide additional support for the dissociation of GMP and parameterization processes.