Learning a Motor Skill: Effects of Blocked Versus Random Practice a Review

Procedural learning refers to the ability to learn new perceptual, motor or cognitive skills. While many studies have explored procedural learning abilities in patients with different types of brain damage, the cognitive mechanisms involved in the acquisition of a new skill are still not well understood. The present review focuses on the conditions that optimise skill acquisition, and more specifically on the contextual interference effect (CIE), which refers to the advantage of a 'random' over a 'blocked' practice condition in skill learning tasks. According to both the 'elaboration' and 'reconstruction' hypotheses, the CIE can be explained by the fact that the random schedule requires more cognitive activity than the blocked one. However, if the CIE has been consistently demonstrated in laboratory studies, it is not so clear in field-based studies. We discuss this 'laboratory and field dilemma', and suggest that two main factors – task complexity and individual variables – may explain the discrepancy between the two types of studies.

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title: Contextual interference effects on the acquisition, retention, and transfer of a motor skill.
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title: A REVIEW OF THE CONTEXTUAL INTERFERENCE EFFECT IN MOTOR SKILL ACQUISITION
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title: Practice schedule effects on the acquisition and retention of a motor skill
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title: Contextual Interference in Motor Learning: Dissociated Effects Due to the Nature of Task Variations
abstract: The contextual interference effect in motor learning refers to the interference that results from practising a task within the concept of other tasks in a practice session. Several studies have shown that practice under conditions of high contextual interference (i.e. with a random practice order) degrades performance during acquisition trials, compared to low contextual interference conditions (i.e. with a blocked order, where practice is completed on one task before practice on another task is undertaken). In contrast to acquisition performance, random practice usually leads to more effective learning than blocked practice, as measured by retention and transfer tests. One of the hypotheses regarding the effect suggests that a random practice schedule induces more extensive planning operations during practice than a blocked practice condition. If so, then differences between these two conditions should emerge to the degree that the set of tasks requires complete reconstruction of these planning operations on each trial. To address this issue, we compared four groups of subjects: a blocked and random group that practised three timing tasks that shared a common characteristic (same relative timing), and a blocked and random group that practised three tasks that each had different relative timing structures. Subjects practised these tasks on each of two days, with a retention test and two transfer tests that required either a relative timing structure that had been practised previously or had not previously been practised. No random/ blocked differences occurred regardless of the relative timing of the patterns during acquisition or retention. However, for both transfer tests, random practice enhanced learning only for the group that had practised with tasks that each had different relative timing during acquisition. Implications of these results for an explanation of contextual interference are discussed.

title: The contextual interference effect for skill variations from the same and different generalized motor programs.
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title: Contextual Interference Effects with Two Tasks
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title: Contextual interference in movements of the same class: differential effects on program and parameter learning.
abstract: Contextual interference effects in motor learning usually were not found when the tasks to be learned presumably required the same generalized motor program (GMP) and differed only with regard to the movement parameters (see Lee, Wulf, & Schmidt, 1992; Magill & Hall, 1990). Thus, tasks requiring different motor programs (e.g., different relative timings) seemed to be a prerequisite for random practice to be more effective than blocked practice. However, the previous studies (that did not find random/blocked differences) used global error measures that confounded errors in relative timing and errors in absolute timing. In the present study, subjects practiced three movement patterns that had the same relative timing (requiring the same GMP) but different overall durations (requiring different parameters). Errors in relative timing and in absolute timing were assessed separately. The results indicate that random practice is more effective for the learning of relative timing (GMP learning) and less effective for the learning of absolute timing (parameter learning) than blocked practice. Preliminary ideas as to the reasons for this effect are discussed.

title: Level of Expertise, Interpolated Activity and Contextual Interference Effects on Memory and Transfer
abstract: Effects of contextual interference on memory and transfer were investigated using tasks of coincident anticipation in which subjects had to predict the arrival time of a light stimulus. Female sport-skill experts were compared to less experienced subjects. A cognitive-motor interpolated activity was performed by one group of subjects, and this condition was compared with blocked and variable practice conditions. This study investigated the 1985 hypothesis of Lee and Magill that forgetting the cognitive processing steps in the performance of a task would facilitate retention. Analysis indicated some support of Battig's predictions mote at retention than transfer but clearly did not support Lee and Magill's views on forgetting. Expertise was a significant factor in acquisition, retention, and transfer since sport experts responded with less error on almost all measures.

title: The effects of contextual interference on females with varied experience in open sport skills.
abstract: The acquisition and transfer effects of contextual interference (Battig, 1979) were investigated on a coincidence anticipation task. The experimental task required subjects to make predictive judgements so that their responses coincided with the arrival of a light stimulus. Sixty females were selected from an activity questionnaire determining the extent of experience in similar tasks. One half were selected reporting no experience, and the remaining subjects had prior and present involvement in tasks requiring predictive judgements. Battig's (1979) conceptualization of memory was supported for experienced subjects in one transfer task. Experienced subjects who processed the acquisition tasks in high contextual interference (random order of presentation) performed significantly better than novice subjects in the same acquisition context. In addition, acquisition under a random sequence facilitated transfer to a novel task for experienced subjects as compared to acquisition under a constant order ...

title: The influence of proficiency level, transfer distality, and gender on the contextual interference effect.
abstract: This study examined the impact of high and low proficiency level, transfer distality, and gender on the contextual interference effect with an open skill. Subjects were separated into two levels of proficiency based on performance on a pretest similar to the experimental task. Analysis of error scores during acquisition indicated that the partitioning of subjects according to ability level had been successful. Transfer distality was varied by presenting subjects with two tasks varying in similarity to the acquisition task. Analysis of absolute constant, constant, variable, and total error scores in transfer strongly suggested that subjects' consistency rather than response bias was affected by the experimental variables. The findings suggested that, for the task used in this study, proficiency level does not account for gender differences in the contextual interference effect, as the effect was only reliably found for females. For coincident timing skills, it appears that there may be two distinct conclusions drawn from the results of this study: contextual interference only benefits female subjects' consistency and the effect of contextual interference increases with the distality of transfer, regardless of the subjects' proficiency level.

title: Contextual interference: Contributions of practice
abstract: The present experiment extends the findings of Shea and Morgan (1979) and Lee and Magill (1983) by determining the impact of manipulating contextual interference in 50, 200, and 400 acquisition trials on retention of a rapid force production task assessed under both random and blocked contexts. Acquisition performance was interior for the random acquisition groups as compared to the blocked groups with little differences between the 50, 200, and 400 acquisition groups' performance at comparable stages of practice. However, the retention data indicated that subjects who completed 400 random acquisition trials performed better on both random and blocked retention than subjects who learned under blocked contexts. Increasing the number of blocked acquisition trials did not improve retention under blocked contexts and had a negative effect on retention assessed under random contexts. Apparently, the benefits of blocked practice (low contextual interference) occur early in practice with response production becoming increasingly more rigid and inflexible. On the other hand, the benefits of random practice (high contextual interference) surface after initial practice.

title: Practice schedule and cognitive style interaction in learning a maze task
abstract: In the present study the effects of contextual interference on the retention and transfer performance of reflectives and impulsives on a maze task were studied. Forty-seven subjects were randomly assigned to either a high contextual interference group or to a low contextual interference group. Within the two groups subjects were further classified according to their preferred modes of responding. Retention and transfer were measured immediately following practice and after a 4-week delay. The dependent variables were tracing time and errors. Reflectives made fewer errors and moved more quickly after practising under conditions of high contextual interference. Impulsives tended to have fewer errors after practising under conditions of high contextual interference but moved more slowly. Based on these results it was suggested that trainers consider individual differences in reflectivity-impulsivity before designing particular practice schedules.

title: Contextual Interference: Interactions with Reflection-Impulsivity
abstract: In the present study, interactions of contextual interference and the cognitive style reflection-impulsivity were examined for training and retention performance. 64 subjects were randomly assigned to either a random or blocked practice schedule in learning a cursor-movement task. Reflectivity indices were determined by means of our computerized version of the Matching Familiar Figures Test. Analysis showed that the generally positive effect of practicing under a random practice schedule decreased for more reflective subjects. Further, training under a random practice schedule forced impulsive subjects to behave more like reflective ones, which improved their performance at retention. It was concluded that reflection-impulsivity is an important factor to be incorporated into the design of effective training programs.

title: Effects of Specific versus Variable Practice on the Retention and Transfer of a Continuous Motor Skill
abstract: The effects of specific versus variable practice on retention and transfer was investigated. 30 participants were randomly assigned to one of three practice conditions. The variable speed group practiced on a pursuit rotor task at three different speeds (60, 45, 30 rpm) which were randomly distributed but equal in number for 30 10-sec. trials on Day 1. The Specific Practice group performed all 30 10-sec. trials at 45 rpm on Day 1. On Day 2, all groups performed 15 trials at the 45-rpm retention speed and 15 trials at the 75-rpm transfer speed. The Control group only performed on Day 2. Analysis showed the Specific Practice group had significantly higher scores on Day 1. On Day 2, the Specific Practice group had significantly higher retention scores and the Variable Practice group had higher transfer scores. Continuous motor skills might be practiced differently depending on the environmental context in which the skill may be used.

title: Task Duration in Contextual Interference
abstract: Duration of practice trial on a pursuit rotor task in contextual interference was investigated. Participants practiced at each of 4 angular velocities, with 24 participants completing 28 trials lasting 20 sec., and 24 participants completing 112 trials of 5 sec. Half of the participants in each trial-duration condition practiced in a blocked format and half practiced in a random format. After random practice posttest performance was better than blocked practice when practice-trial duration was 20 sec., but worse when practice-trial duration was 5 sec. This result is not consistent with theoretical explanations of the contextual interference effect and is discussed with reference to the task characteristics and demands of the pursuit rotor.

title: Contextual interference in learning new patterns of bimanual coordination.
abstract: Two experiments are reported in which the question of whether or not contextual interference effects are found in motor tasks that require the acquisition of new coordination patterns was examined. Participants (N = 18, Experiment 1; N = 12, Experiment 2) practiced 3 novel bimanual patterns (45 degrees , 90 degrees , and 135 degrees relative phase) in either a random or a blocked order. No statistically significant acquisition or retention differences between groups were found when all 3 patterns were practiced on each of 2 days (Experiment 1). When the blocked group practiced 1 pattern on each of 3 acquisition days (Experiment 2), however, typical contextual interference effects were found: The blocked group performed better than the random group in practice, but the random group performed better than the blocked group in a delayed (by I week) retention test. The experiments revealed that contextual interference effects can arise in motor tasks that require the acquisition of new coordination patterns and are not limited to tasks involving novel scaling of a previously existing pattern.

title: A schema theory of discrete motor skill learning.
abstract: A number of closed-loop postulations to explain motor skills learning and performance phenomena have appeared recently, but each of these views suffers from either (a) logical problems in explaining the phenomena or (b) predictions that are not supported by the empirical evidence. After these difficulties are discussed, a new theory for discrete motor learning is proposed that seems capable of explaining the existing findings. The theory is based on the notion of the schema and uses a recall memory to produce movement and a recognition memory to evaluate response correctness. Some of the predictions are mentioned, research techniques and paradigms that can be used to test the predictions are listed, and data in support of the theory are presented.

title: Complex movement behaviour : 'the' motor-action controversy
abstract: Setting the Stage: `The' Motor-Action Controversy. .  Empirical Studies.  Bootsma, P.C.W. van Wieringen T.D. Lee K.-H. Leist R.A. Magill T. Mulder, W. Hulstijn K. Roth J.B. Shea, S.T. Zimny S. Swinnen W.H. Warren, Jr. H.T.A. Whiting). Motor and Action Approaches: Theoretical Considerations.

title: Deficient Processing in Learning and Performance
abstract: Two experiments investigated the assumption made by Shea and Zimny (1983) in their recently proposed theoretical framework for contextual interference that recognition and recall performance are at least partially separable and can be independently manipulated. In both experiments, recognition training prior to acquisition resulted in fewer tasks being recalled for the recognition training condition than for the non-task recognition and no-recognition training conditions. We offer an explanation in which recognition training enabled subjects to solely use identification processes to keep the tasks in working memory and allow subsequent motor performance. These identification processes, however, did not provide detailed enough knowledge of the tasks to support recall performance (i.e. deficient processing). These findings are interpreted within a parallel-distributed processing view of learning and performance.

title: The contribution of elaborative processing to the contextual interference effect.
abstract: This study examined the influence of supplemental intertask and intratask processing on the retention of three motor sequences practiced in conditions of high and low contextual interference. Subjects practiced in either a blocked or random practice format and experienced additional intratask processing, intertask processing, or no additional processing. Each of three movement sequences were practiced for 18 trials. The subjects were required to perform the sequences as fast and as accurately as possible. Retention performance and recall of the movement sequences were assessed after a 21-day retention interval. The results replicated those of Wright (1991), indicating a benefit for individuals engaging intertask processing during a low contextual interference practice condition. Furthermore, supplementing random practice with additional intertask processing not only slowed the rate of task acquisition, but also resulted in retention performance that was significantly poorer than that exhibited by individuals exposed to random practice with no additional processing. This suggests there may be a limit to the extent of interference that can be established during practice that will lead to a facilitation in retention performance.

title: Influence of practice schedule on testing schema theory predictions in adults.
abstract: Since the publication of Schmidt's (1975) schema theory of motor learning, numerous studies have assessed the variability of practice hypothesis. Of these, only research using children as subjects has provided consistent results. Findings from adult studies have been equivocal. Two experiments were conducted to assess the possibility that the schedule of variable practice during acquisition may be a clue to this equivocality, since only experiments (using adults as subjects) that have provide random variability of practice conditions have consistently supported the tenets of schema theory. Using a two movement rapid timing task, subjects learned to control their actions under one (constant) or four (variable) parameters, with variable practice conducted under either a blocked or a randomized schedule. Results for variable error and absolute constant error showed that random-variable practice provided strong support for the schema theory prediction, whereas blocked-variable practice provided only relatively weak support. Two contrasting implications of these results are discussed with respect to support versus non-support for Schmidt' schema theory.

title: An Assessment of the Attention Demands during Random- and Blocked-Practice Schedules
abstract: The reported study used the dual-task methodology to assess the attention demands associated with high and low contextual interference (CI) practice environments. Two specific issues were addressed. First, is there a difference in the attention demands during random and blocked schedules of practice? Second, what is the time course of any differential attention demands that emerge during random and blocked training? In order to address these questions two specific temporal loci were probed during practice: a pre-response interval and the inter-trial interval. It was assumed that the pre-response interval contained the reconstructive activity that is central to the reconstruction position. In contrast, the inter-trial interval has been interpreted in previous work to be the interval in which critical intra- and inter-item processing is performed during random practice. The data revealed a typical CI effect for the primary key-pressing task. Specifically, blocked-practice participants displayed superior performance during training but performed less well than the random-practice individuals at the time of retention. The poorer acquisition performance of the random practice participants was associated with higher cognitive demand during both the pre-response and the inter-trial intervals than that of individuals assigned to blocked practice. The greater attention demands for random-practice individuals are discussed with respect to processes that might occur in both the pre-response and the inter-trial intervals.

title: Contextual Interference: A Response Planning Account
abstract: In two of the three experiments that are reported subjects were trained in either a blocked or a random practice schedule and allowed to self-select the amount of time they used to plan an upcoming movement. According to the reconstruction hypothesis (Lee & Magill, 1985) random practice participants engage greater movement planning processes (i.e. action plan re-construction) during acquisition than do their blocked practice counterparts. It was predicted that such reconstructive activity would be manifest as greater study time being used by random practice subjects as they readied themselves for an imminent response. Data from Experiments 1 and 2 supported this study time prediction while also revealing the typical retention benefit associated with random practice. Interestingly, the acquisition benefit often apparent with blocked practice was not evident when the random practice participants were given sufficient time to plan the upcoming response. These conclusions were supported by data from Experiment 3 that involved a direct manipulation of the amount of study time afforded random and blocked practice participants. Taken together, these data are consistent with the suggestion from the reconstruction hypothesis that more time is necessary for intratrial planning processes during random practice formats. Furthermore, acquisition differences that are commonly observed between high and low contextual interference practice conditions may, at least in part, be associated with the completion of the extra planning processes entertained by random practice participants as the movement is being executed.

title: Neural Substrates of Contextual Interference during Motor Learning Support a Model of Active Preparation
abstract: When individuals acquire new skills, initial performance is typically better and tasks are judged to be easier when the tasks are segregated and practiced by block, compared to when different tasks are randomly intermixed in practice. However, subsequent skill retention is better for a randomly practiced group, an effect known as contextual interference (CI). The present study examined the neural substrates of CI using functional magnetic resonance imaging (fMRI). Individuals learned a set of three 4-element sequences with the left hand according to a block or random practice schedule. Behavioral retest for skill retention confirmed the presence of a typical CI effect with the random group outperforming the block group. Using a go/no-go fMRI paradigm, sequence preparation during the premovement study period was separated from movement execution. Imaging data for the two groups were compared for the first 1/3 and final 1/3 of training trials. Toward the end of training, behavioral performance between the two groups was similar, although the random group would later display a performance advantage on retention testing. During study time, the random group showed greater activity in sensorimotor and premotor regions compared to the block group. These areas are associated with motor preparation, sequencing, and response selection. This pattern of recruitment is consistent with the hypothesis that CI benefits in a sequencing task are due to improved capacity to actively prepare motor responses.

title: The influence of reminder trials on contextual interference effects.
abstract: Two experiments investigated the proposition of the elaboration explanation for contextual interference that more than one task is present in working memory when multiple tasks are practiced in a random schedule but that only one task is present in working memory when multiple tasks are practiced in a blocked schedule. Three motor tasks were performed as fast as possible in either a random or blocked practice schedule. At the end of practice, a reminder trial for each task was either given or not given. Acquisition performance was slower for the random practice conditions than for the blocked practice conditions. Retention performance was faster for the random practice conditions than for the blocked practice condition that did not receive a reminder trial for each task. Importantly, performance differences were not found between the random practice conditions and the blocked practice condition that did receive a reminder trial for each task. A blocked practice condition with a beneficial acquisition and reminder task order pairing performed faster during both acquisition and retention than a comparable random practice condition. Reminder trials can facilitate detailing of task characteristics, and their effectiveness is determined by the elapsed time and number of intervening tasks during acquisition and retention.

title: Contextual interference and motor skill acquisition: On the processes that influence retention
abstract: Over the last decade, there have been competing explanations for the contextual interference effect in motor learning. One notion (Lee and Magill 1983) describes the effect in terms of the movement-plan reconstruction processes acquired with practice, while an alternative (Shea and Zimny 1983, 1988) emphasizes that the types of multiple processing strategies developed with practice are responsible for the effect. In this project, we examined how the various processes, as proposed by both of these explanations, influence the acquisition and retention of a simple aiming task. The methodology employed to address this problem supplemented practice schedules with various interpolated activities in the post-KR delay interval. In experiment 1, exemplar modals about the same-trial, next, or other (randomly determined) movement goal were provided to random practice conditions. Results indicated that there were detrimental and slight beneficial effects for retention when these types of models were provided, relative to a control condition. Experiment 2 further examined the post-KR delay activities that could enhance the cognitive processing associated with effective retention in both blocked and random practice. Findings from this experiment indicate that different types of interpolated activities presented in the post-KR delay interval facilitate retention for blocked practice conditions. Together, results from both experiments suggest that both elaboration and reconstruction processes can be beneficial for long-term retention.

title: Schema Theory: Critical Review and Implications for the Role of Cognition in a New Theory of Motor Learning
abstract: This paper is based on a symposium celebrating the 26th anniversary of the publication of“A Schema Theory of Discrete Motor Skill Learning” (Schmidt, 1975) held at the annual conference of the North American Society for the Psychology of Sport and Physical Activity in June 2001. We provide a brief historical context for schema theory and a review of the development of the mechanistic approach to motor learning in general. We explore recent findings in mental practice, observational learning, augmented feedback presentation, and the variability of practice that are inconsistent with schema theory and provide a rationale for the importance of cognitive activity in motor learning.

title: Contextual Interference Effect on Acquisition and Retention of Pistol-Shooting Skills
abstract: The effects of contextual interference on learning pistol-shooting skills in a natural training environment were examined. The shooting skills consisted of three “stages” with different requirements for the skill variations commonly used in the field. 12 participants were randomly assigned into one of two practice conditions, blocked vs serial. Following a 20-min. safety and skill instructional session, Blocked group practiced 10 trials in a row at each stage, while Serial group performed 5 trials in a row for each of the three stages and then repeated the cycle. Both groups completed a total of 30 practice trials over the three stages. A 10-min. rest interval was provided prior to a retention test which included 9 trials (3 trials at each stage in a blocked format). Results based on the data of Stage III, the most complex skill among the three stages, showed a pattern consistent with previous findings that practicing in the serial schedule depressed performance during initial training but maintained the performance better at retention, relative to the blocked practice.

title: Contextual Interference: A Meta-Analytic Study
abstract: A meta-analysis of the contextual interference effect produced 139 estimates of effect sizes from 61 studies. The average overall effect size was .38. The effect size for basic research (.57) was significantly different from applied research (.19). Significant differences were also obtained between the effect sizes for adults (.50) and those for younger learners (.10). Power for retention and transfer scores was not significantly different. The overall mean power of the studies reviewed was .43.

title: The Contextual Interference Effect and Sport Skills
abstract: During the last twenty-five years, the contextual interference effect has been thoroughly studied. This review finds that the effect is relatively robust in basic research, but considerably weaker in applied settings. Motor learning scholars have urged practitioners to develop instructional strategies based upon the inferences of the contextual interference effect. The smaller effects seem to indicate that the concept may have more limited use for the physical educator. It appears that the generalization of procedures from other domains may not adequately accommodate the complexity of motor skills. Manipulating the task difficulty, both nominal and functional, and the contextual continuum may be a promising route for the practitioner.

title: Relevance, Application, and the Development of an Unlikely Theory
abstract: This paper advances the argument that motor learning research is not relevant to the needs and interests of motor skill teachers. The principal reason is that motor learning researchers in university departments of physical education have responded to calls for paradigmatic shifts that were intended for experimental psychologists, not necessarily for researchers from departments of physical education. As a result, motor learning researchers have concentrated their efforts on studying the mechanisms underlying motor performance rather than on devising and testing ways to improve motor performance. The body of knowledge produced by this approach has been based on experiments employing laboratory tasks and treatment conditions that lack fidelity to those appropriate or even possible in real-world teaching environments. Consequently, little knowledge has been produced that can be directly applied to the technical aspects of teaching. It also is argued that progress toward an applied thrust has been hindered b...

title: Motor Learning Research: Meaningful Ways for Physical Educators or a Waste of Time?
abstract: I attempt to provide a framework for the subsequent position papers by offering perceptions about the nature of motor learning research and various factors affecting its focus, quality, and depth. Historical antecedents and present conditions help to explain the course that the motor learning specialization is taking, with implications for the potential meaningfulness of the research to pedagogy and to the advancement of a body of knowledge. A number of variables confound the analysis, including the identification and growth of specializations referred to as motor control and sport psychology (and their interpreted relationship to motor learning), the ability to determine what in fact constitutes motor learning research, the judgment as to what research is user friendly (of potential benefit to physical educators), and the question as to who is responsible for making practical sense of the literature: the scholar or the practitioner.

title: Contextual Interference Effects in Learning Three Badminton Serves
abstract: This study investigated the generalizability of results of contextual interference effects by extending previous laboratory research to a field setting. Thirty female subjects (N = 30) learned three badminton serves in either a blocked (low interference), serial (mixed interference), or random (high interference) practice schedule. The subjects practiced the serves three days a week for three weeks. On the day following the completion of practice the subjects were given a retention and transfer test. Results replicated previous findings of contextual interference research by showing a significant group by block interaction between acquisition trials, retention, and transfer. The random group performed better on both retention and transfer than the blocked group. The significant trial block by contextual interference interaction also supports the generalizability of contextual interference effects, as posited by Shea and Morgan (1979), to the teaching of motor skills.

title: Contextual interference effects with skilled baseball players.
abstract: The learning benefits of contextual interference have been frequently demonstrated in different settings using novice learners. The purpose of the present study was to test such effects with skilled athletic performers. Scheduling differences for biweekly additional ("extra") batting-practice sessions of a collegiate baseball team were examined. 30 players (ns = 10) were blocked on skill and then randomly assigned to one of three groups. The random and blocked groups received 2 additional batting-practice sessions each week for 6 wk. (12 sessions), while the control group received no additional practice. The extra sessions consisted of 45 pitches, 15 fastballs, 15 curveballs, and 15 change-up pitches. The random group received these pitches in a random order, while the blocked group received all 15 of one type, then 15 of the next type, and finally 15 of the last type of pitch in a blocked fashion. All subjects received a pretest of 45 randomly presented pitches of the three varieties. After 6 wk. of extra batting practice, all subjects received two transfer tests, each of 45 trials; one was presented randomly and one blocked. The transfer tests were counterbalanced across subjects. Pretest analysis showed no significant differences among groups. On both the random and blocked transfer tests, however, the random group performed with reliably higher scores than the blocked group, who performed better than the control group. When comparing the pretest to the random transfer test, the random group improved 56.7%, the blocked group 24.8%, and the control group only 6.2%.(ABSTRACT TRUNCATED AT 250 WORDS)

title: Long-Term Effects of Type of Practice on the Learning and Transfer of a Complex Motor Skill
abstract: This study analyzed the long-term effects of practice schedule on shooting performance in basketball during actual field training. 32 college students (16 female) ages 20 to 29 years completed voluntary basketball training in one of two equal-sized groups employing either constant versus random training. The constant practice group took 160 shots from the free throw line, while the variable practice group took 160 shots from different positions around the restricted area. Learning and transfer (variation of throwing distance and size of the ball) performance was assessed with the Basketball-Shooting Test before and after training and on a retention test 1 yr. later. Significant measures in performance were attributed to learning and transfer in both training groups at all measurement times. Constant training groups had better acquisition and random training groups had better retention. The anticipated transfer effect in the random group was not found.

title: Is the Contextual Interference Effect Generalizable to Computer Games?
abstract: The benefits of learning multiple tasks under an unstructured practice schedule have been extensively demonstrated in the laboratory. The purpose of the present study was to test contextual interference effects in a nonlaboratory setting using computer games as tasks. Undergraduate kinesiology and sport management majors (N=19) played a computer game simulating the events of the winter Olympics. Participants were randomly assigned to either a Blocked or Random practice schedule, practicing 36 trials of three events. Delayed retention and transfer tests were performed after a 48-hr. retention interval. The dependent variable was time to complete an event. During transfer, participants in the Random schedule (M = 248 sec.) were significantly faster than Blocked (M = 263 sec.) participants. Results support and extend previous contextual interference findings. Transfer was facilitated for participants who learned the events in a Random practice order. Results are discussed in terms of the influence of task characteristics on learning.

title: A comparison of three practice schedules along the contextual interference continuum.
abstract: T he organization of practice sessions is recognized as one of the most important functions teachers and coaches perform (Silverman, 1990; Vickers, 1990). However, as noted by Newel1 and McDonald (1992), despite considerable interest among researchers and practitioners, clear guidelines for organizing practice sessions have yet to be formulated. Magill (1992) has argued that the practice schedule research provides a knowledge base from which guidelines can be developed. This research, ongoing for over a decade, has compared the effects of practice schedules, which represent levels of contextual interference, on the performance and learning of motor skills. Predominately laboratory based, this research has produced an impressive set of findings (for a review, see Magill & Hall, 1990). However, replication of these findings in applied settings has been difficult, and questions regarding the applicability of contextual interference have been raised (Newel1 & McDonald, 1992).

title: The effect of contextual variety on the practice, retention, and transfer of an applied motor skill.
abstract: Laboratory research in motor learning has consistently demonstrated higher retention and/or transfer when practice occurs under conditions of high contextual variety (e.g., Lee & Magill, 1983; Newell & Shapiro, 1976; Shea & Morgan, 1979;). In the present study, an attempt was made to determine whether a contextual variety effect could be demonstrated in a standard physical education instructional setting. During practice trials on the long and short badminton serves, male and female subjects performed under either blocked (i.e., all trials of one serve followed by all trials of the other) or varied (i.e., alternating trials of long and short serves) conditions. Retention and transfer tests (i.e., using the service area opposite that employed during the practice phase) were administered at the end of the badminton unit. Although little difference was observed in the performance of the two groups during practice, alternating-trial subjects demonstrated significantly higher retention of the short serve and significantly higher transfer of both serves than blocked-trial subjects. The performance of male and female subjects was not differentially influenced by practice structure conditions. It was concluded that a practice schedule that requires performers to change their plan of action from trial to trial may facilitate the retention and transfer of motor skills in applied instructional settings.

title: The effects of the amount and variability of practice on the learning of a multi-segmented motor task.
abstract: Since the Shea, J.B. and Morgan (1979) study, investigators have repeatedly shown that the learning of a set of movement patterns (as evaluated in a retention test) is enhanced when acquisition occurred under a random rather than a blocked schedule of practice. Supposedly, this is the case because a random schedule of practice necessitates more elaborate cognitive activities than a blocked schedule before each acquisition trial can be initiated. Our main objective was to determine whether the advantage for learning found for random practice increases as a function of the number of acquisition trials. During acquisition, the results indicated a general tendency for smaller movement reproduction errors under a blocked rather than a random schedule of practice. However, this effect disappeared with larger amount of acquisition trials. In retention, larger errors were observed when acquisition occurred under a blocked rather than a random schedule of practice. Finally, the disadvantage for learning observed for the blocked schedule of practice disappeared under a block-repeated condition in which each movement pattern was first practiced under a blocked schedule which was then repeated a second time. The results are discussed in terms of the so-called contextual interference effect and indicates some of its limitations.

title: Effects of Contextual Interference on Retention of Three Volleyball Skills
abstract: Previous research in motor learning has shown that random practice schedules facilitate retention and transfer of motor skills more than repetitive practice schedules. The purpose of this study was to investigate the generalizability of contextual interference effects. High school students (63 boys, 76 girls) from three physical education class periods were randomly assigned to one of three practice conditions, random, random-blocked, or blocked practice within a class period. Three teachers were randomly assigned to a practice group within a class period and taught a different practice condition each class period. There were nine groups with three practice groups per class period. Subjects practiced the volleyball forearm pass, set, or overhead serve for 30 trials every day for nine class periods. All subjects recorded scores for their practice trials each day during acquisition and were posttested after a 2-day retention interval. Analysis of variance indicated significant improvement in all groups but no significant effects of practice condition during acquisition or retention. These findings suggest that practice was long enough to produce change during acquisition. However, factors characteristic of physical education classes may reduce or mask contextual interference effects commonly observed in other settings.

title: Effects of Contextual Interference on Acquisition and Retention of Three Volleyball Skills
abstract: Manipulating the organization of practice conditions, through contextual interference, was identified as a method to promote motor skill acquisition by Brady in 1998. The generalizability of this learning effect is questionable and the amount of repetition versus the amount of change in task presentation requires investigation. The purpose of this study was to explore explanations for the performance of learners practicing the AAHPERD volleyball skills test when the change in task presentation varied. High school students were randomly assigned to blocked, random, and random-blocked practice groups. While all groups significantly improved all skills during acquisition, there was no support for the contextual interference effect. Potential explanations might be dependent upon the learners' skill and the complexity of the task to be learned. Further research is warranted examining contextual interference effect on practice organization at levels of difficulty appropriate to facilitate cognitive processing of task-related information.

title: Contextual Interference Effects in Learning Volleyball Skills
abstract: The aim of this study was to examine the contextual interference effect on learning three volleyball skills. Participants were 26 novice female volleyball players (M age = 12.4 yr., SD = 1.2). They were assigned into two groups, Low Interference (n = 13) and High Interference (n = 13). Two practice schedules were used: blocked (Low Interference) and random (High Interference). The training period lasted for 10 weeks and included 2 training sessions of 75 min. each per week. The pretest was performed before the first training session, the posttest was performed after the completion of the last training period, and the retention test was performed two weeks after the posttest. A 2 (Groups) × 3 (Measurement Periods) analysis of variance with repeated measures indicated significant improvement in performance between pre- and posttests for both High Interference and Low Interference groups for the three skills included in this study. There was no significant main effect of group or interaction effect of group and measure. These findings suggest that either blocked or random practice could be effectively used in learning of volleyball skills by unskilled children.

title: Effects of Contextual Interference on Learning Technical Sports Skills
abstract: The effects of contextual interference on learning skills of volleyball (volley, bump, serve) are influenced by the scheduling of actual practice sessions: the activities can be proposed in a repetitive practice schedule (blocked practice) by continuously repeating the same task (low interference) or in random practice schedules by performing more tasks or variations of one same activity (high interference). High contextual interference, even though causing immediate limited performance, leads to superior performance on retention and transfer tests. Four experimental groups (13 students each) were placed in conditions of random, blocked, serial, and serial with high interference practice for 8 meetings (2 tests and 6 practice). Analysis yielded significant differences among the groups on a transfer test (long transfer) for the serve, so results in this instructional setting are partially in line with those generally found in laboratory experiments.

title: Contextual Interference and Teaching Golf Skills
abstract: This study was designed to examine the contextual interference effect on teaching golf skills in a naturalistic setting to 2 groups of 18 novice golfers who as undergraduate students practiced four foundational skills under conditions of low and high contextual interference, respectively. A t test for independent samples indicated no significant differences between groups. Findings are discussed and recommendations for research are made.

title: Investigation of the Contextual Interference Effect in the Manipulation of the Motor Parameter of Over-All Force
abstract: This investigation examined the contextual interference effect when manipulating over-all force in a golf-putting task. Undergraduate women (N = 30) were randomly assigned to a Random, Blocked-Random, or Blocked practice condition and practiced golf putting from distances of 2.43 m, 3.95 m, and 5.47 m during acquisition. Subjects in the Random condition practiced trials in a quasirandom sequence and those in the Blocked-Random condition practiced trials initially in a blocked sequence with the remainder of the trials practiced in a quasirandom sequence. In the Blocked condition subjects practiced trials in a blocked sequence. A 24-hr. transfer test consisted of 30 trials with 10 trials each from 1.67 m, 3.19 m, and 6.23 m. Transfer scores supported the Magill and Hall (1990) hypothesis that, when task variations involve learning parameters of a generalized motor program, the benefit of random practice over blocked practice would not be found.

title: Rehearsal of Task Variations and Contextual Interference Effect in a Field Setting
abstract: The present study showed a consistent pattern with a typical contextual interference effect in motor skill learning (N = 38 adults). Individuals trained under the high contextual interference condition may receive greater learning benefits than those under the low contextual interference condition during the rehearsal of task variations of a single motor skill in a field setting.

title: Effect of Different Quantities of Variable Practice on Acquisition, Retention, and Transfer of An Applied Motor Skill
abstract: This investigation examined the effect of manipulating different quantities of variable practice in the acquisition phase on the retention and transfer performance of a dart throw. Participants in the Specific condition practiced a total of 75 acquisition trials from a distance of 2.39 m. Participants in the Specific + Variable condition practiced a total of 75 acquisition trials with 25 trials from distances of 1.47 m, 2.39 m, and 3.30 m. Participants in the Specific + Varplus condition practiced a total of 75 acquisition trials with 15 trials from distances of 1.47 m, 1.93 m, 2.39 m, 2.84 m, and 3.30 m. Results of the one-way analysis of variance on the 24-hr. retention test from 2.39 m yielded no significant differences among practice conditions for mean radial error. A one-way analysis of variance on the 24-hr. transfer test from 3.76 m indicated that the Specific + Variable and Specific + Varplus conditions performed with significantly smaller mean radial error than the Specific condition. The results are discussed in regard to recent research and applicability to instructional settings.

title: The Contextual Interference Effect in Acquisition of Dart-Throwing Skill Tested on a Transfer Test with Extended Trials
abstract: Previous studies of contextual interference have shown that practicing several motor skills randomly (high contextual interference) facilitates retention and transfer in comparison to practicing the same tasks in a blocked order (low contextual interference). However, many studies have not supported this phenomenon in motor learning, and some researchers have questioned whether the effect can be tested by using only a few trials on the transfer test. The present study used a different methodological approach in which the number of test trials was increased to assess whether the contextual interference effect is sustained over an extended number of trials in the transfer phase. Undergraduate students (N = 32) were randomly allocated to either a blocked or random group. The participants practiced 80 acquisition trials in the dart-throwing task from distances of 300 cm and 420 cm, using two different grips. The transfer test after a 10-min. interval consisted of 40 trials with a new grip at a distance of 360 cm. The results did not support the contextual interference effect since there were no significant differences between groups on transfer. These findings suggest that the contextual interference effect may not be a global learning phenomenon which can be generalized to all learning situations.

title: Contextual Interference in Learning Precision Skills
abstract: This research studied the effect of different organisations of practice (blocked and random) on the learning of three different types of throwing. 35 male students practiced three precise throws for 3 wk. Initially the subjects were separated into two groups who trained under different conditions of practice (blocked and random). All subjects improved significantly from initial performance, with both blocked practice and random practice. At the end of acquisition no differences were found between the groups. No significant differences were found on retention tests carried out 48 hr., 4 wk., and 8 wk. after the training period.

title: Contextual Interference Effects in Learning Novel Motor Skills
abstract: The present study investigated the generalizability of contextual interference effects by extending previous laboratory and field research to novel movements controlled by different motor programs. 30 men and 33 women learned novel throwing and kicking tasks, practicing with blocked, serial, or random schedules. The subjects practiced the tasks four days a week for two weeks and then were given a postest. One week later subjects were given a retention test. Significant improvements in performance were found for all groups for both tasks; however, a significant effect for practice condition was found only for the throwing task during retention, for which the random practice schedule led to better learning than the blocked and the serial practice. These findings suggest that the blocked, serial, and random practice methods could be effectively used for tasks controlled by different motor programs but must be practiced in the same teaching session, without expecting one to be more effective in learning than any other.

title: The contextual interference effect in applied settings
abstract: This paper analyses the research literature that approaches the contextual interference effect in applied settings. In contrast to the laboratory settings, in which high interference conditions depress acquisition and promote learning evaluated in retention and transfer tests, in applied settings most of the studies (60%) fail to observe positive effects after manipulation of the contextual interference. Some possible explanations for the fact are hypothesized regarding the characteristics of the task, with serial tasks doing best, shor t inter trial intervals rare in applied settings, interference produced by the use of different motor programmes and the possible interference of concurrent feedback in slow tasks in contrast to ballistic skills. It seems that there is a more evident contextual interference effect in an applied setting, when subject learns a serial task with high degree of complexity.

title: Influence of an unskilled model's practice schedule on observational motor learning
abstract: (1986) found that observational learning was quite good when the observer watched an unskilled model improve on a task. By watching the unskilled model improve, the observer engaged in the types of problem-solving activities that characterize motor learning. Engagement in these processing activities was enhanced when the model's KR was also available, perhaps due to the enrichment of the observable information. We report two experiments that attempted to enhance observational learning effects. Adams' paradigm was used in these studies: observers watched unskilled models practise a task over a series of trials during which both the observer and the model were provided with the model's KR. Observers were then assessed for their performance on the task. Subjects were initially tested in pairs whereby the model performed under either a random or blocked practice schedule. The rationale was that since random practice schedules enhance the processing activities of someone learning a movement skill, we hypothesized that there should be a benefit for someone observing the learning of a motor skill as well. This prediction was not supported in either the learning of a computer game (experiment 1) or the learning of a timing task (experiment 2). Although there was a significant observational learning effect in both experiments, there was no influence of the practice schedule on the magnitude of this effect. These findings are discussed relative to theoretical issues of both obsrvational learning and contextual interference effects.

title: Principles derived from the study of simple skills do not generalize to complex skill learning
abstract: We review research related to the learning of complex motor skills with respect to principles developed on the basis of simple skill learning. Although some factors seem to have opposite effects on the learning of simple and of complex skills, other factors appear to be relevant mainly for the learning of more complex skills. We interpret these apparently contradictory findings as suggesting that situations with low processing demands benefit from practice conditions that increase the load and challenge the performer, whereas practice conditions that result in extremely high load should benefit from conditions that reduce the load to more manageable levels. The findings reviewed here call into question the generalizability of results from studies using simple laboratory tasks to the learning of complex motor skills. They also demonstrate the need to use more complex skills in motor-learning research in order to gain further insights into the learning process.

title: Attention and the Contextual Interference Effect for a Continuous Task
abstract: Many studies have shown that practicing several motor tasks in a random (high contextual interference) order promotes motor learning relative to practicing the same tasks in a blocked order (low contextual interference). The facilitative effect of high contextual interference has been attributed to more frequent intertask comparisons, greater difficulty in recalling task solutions between trials, and the dissimilarity among the various tasks. Each of these explanations suggests that task difficulty is increased by high contextual interference. The hypothesis of this study was that this increase in task difficulty during practice would be associated with a higher attention load during practice. This hypothesis was supported; however, high contextual interference promoted only a transient increase in retention. The short-lived effect was attributed to the continuous nature of the task and was discussed in terms of the necessary conditions for contextual interference to emerge.

title: Differential effects of task complexity on contextual interference in a drawing task.
abstract: A large number of studies demonstrated the beneficial effects of contextual interference (CI) created by a random practice of different task variations during training on the retention and transfer of motor skills. Current interpretations of this phenomenon assume that random practice engages the subjects in deep and elaborate processing of movement related information, whereas blocked practice results in more superficial processing leading to poorer performance on later retention and transfer tests. According to this line of interpretation, we hypothesised that the complexity of the task to be learned could modulate the effects of CI. If the task is sufficiently complex, it could force the subjects to rely on such elaborate processing, and the beneficial effects of the intertask interference created by random practice could be obscured in that case. We tested this hypothesis by analysing the effects of practice schedule (random vs. blocked), on the acquisition, retention and transfer of learning in a drawing task where subjects had to reproduce accurately, without visual control, geometrical patterns presented on a video screen, as a function of task complexity defined by the number of segments (two, three or four) of each pattern. The results indicated a clear beneficial effect of random over blocked practice on delayed retention and transfer. However, this CI effect was only observed in subjects who learned the simplest movements, and was not observed in subjects who practised the more complex task. These results are discussed in terms of intratask interference created by the planning of multiple movements and the processing of knowledge of results (KR) when the number of drawing movements is increased. These findings support the assumption that the level of cognitive effort in which the subjects are engaged during training is a main factor influencing long-term retention and transfer of motor skills.

title: Differential Transfer Benefits of Increased Practice for Constant, Blocked, and Serial Practice Schedules
abstract: The effects of practice schedule and amount of practice on the development of the generalized motor program (GMP) and on parameter estimation were investigated. Participants (N = 108) practiced the same relative timing but different absolute durations of a multisegment timing task. Practice schedules (constant, blocked, or serial) were crossed with amounts of practice (low and high). Inclusion of a constant practice condition allowed the authors to investigate the variability of practice prediction. Participants practiced the same proportional durations in a serial or a blocked schedule, which enabled the authors to examine contextual interference. A constant practice schedule enhanced GMP performance when task parameters remained the same, but varied practice schedules were beneficial when task parameters changed. A serial as opposed to a blocked practice schedule was superior when the performance of a task governed by a different GMP was required. Increased practice led to a consolidated task representation that was unavailable for updating.

title: Variability of Practice and Contextual Interference in Motor Skill Learning.
abstract: The purpose of this study was to investigate whether learning benefits in multiple-task learning situations are a result of contextual interference or of schema enhancement related to the amount of variability in the practice session. Two experiments were designed that replicated and extended the experiment reported by Wulf and Schmidt (1988). In a 2 (same vs. different relative time) x 2 (blocked vs. random practice schedule) design, 48 right-handed subjects were randomly assigned to one of four experimental conditions. A tapping task was employed that required a right-handed tap of three small brass plates arranged in a diamond pattern. Each segment had a specific time requirement. Target times and response times were provided on a computer screen directly in front of the subject. Each subject participated in two acquisition sessions (i.e., 198 practice trials) and was tested for learning on several different retention and transfer tests. In Experiment 2, a control group was added that received no acquisition phase. Results of both experiments showed a typical contextual interference effect, with depressed scores by the random groups during acquisition but significantly better scores than the blocked groups on several retention and transfer tests. Certain characteristics of the tests were found to influence the demonstration of the practice schedule effects. These results were consistent with predictions from Magill and Hall (1990) that the learning benefits of contextual interference are more likely to occur when skill variations are from different classes of movement and that the amount of variability in practice is more influential when the to-be-learned tasks are parameter modifications of the same generalized motor program.

title: The contextual interference effect in parameter modifications of the same generalized motor program.
abstract: This study extended previous work (Sekiya, Magill, Sidaway, & Anderson, 1994) by examining whether the contextual interference (CI) effect could be found when task variations were controlled by the same generalized motor program (GMP) but differentiated on the basis of overall force parameter modifications. A subsidiary aim of this study was to determine how the amount of practice influenced the CI effect. During 2 acquisition sessions and 2 retention sessions, participants (N = 24) performed 3 task variations in either a blocked (low CI) or serial (high CI) condition. The task variations shared the same relative force structures but differed in the amount of overall force that had to be produced. Analysis of a general error measure revealed a strong CI effect, indicating that overall force parameter modifications of the same GMP created the CI effect. Analyses of various dependent measures, which dissociated GMP from parameter components with regard to force characteristics, revealed that parameter learning, but not GMP learning, was enhanced by high CI practice. No CI effect occurred in any aspect of timing characteristics. The amount of practice used in the present study did not influence the efficacy of the CI effect.

title: Effects of Blocked versus Random Practice by Mentally Retarded Subjects on Learning a Novel Skill
abstract: The purpose of this study was to assess the effects of different practice conditions on mentally retarded subjects learning a novel task. 20 subjects with a mean IQ of 51.82 were randomly assigned to one of two practice conditions. The first group practiced at three different speeds (60, 30, and 15 rpm) on the pursuit rotor using a block arrangement in which each speed was practiced for five consecutive trials of 20 sec. duration before practicing at the next speed. The second group used random practice performing 15 trials of the pursuit rotor so three speeds were randomly distributed over the 15 trials. Both groups on the next day performed 15 trials of 20 sec. duration on the pursuit rotor at the transfer speed of 45 rpm. Analysis showed no significant differences among practice conditions which provided 10 min. of experience prior to test.

title: Effects of Contextual Interference, Task Difficulty, and Levels of Processing on Pursuit Tracking
abstract: Based on an activity questionnaire, 48 females without experience in open sports skills were selected to track a moving light beam through either a circle, square, or triangular target area on a pursuit rotor. Contextual interference was created by presenting 5 velocities in either a random or a blocked context during acquisition. Level of processing was manipulated by having half of all subjects classify acquisition velocities by a predetermined numerical code. Time-on-target (TOT) was measured after each acquisition, retention, and transfer trial. Subjects tracking the circle produced higher TOTs than those who tracked the square or triangle (which did not differ from one another) across all three phases of the experiment; blocked and random acquisition groups were not significantly different from one another in acquisition, retention, or transfer. Subjects who classified acquisition velocities and tracked the circle under the blocked acquisition context produced significantly higher retention scores than those who tracked the circle but did not classify acquisition velocities. Transfer was facilitated for subjects who tracked the triangle in a random transfer context and classified velocities during acquisition. Results were discussed as providing support for the manipulation of the level of cognitive processing during the initial stage of learning. In addition, manipulating task difficulty was discussed.

title: Role of elaborative and perceptual integrative processes in perceptual-motor performance.
abstract: Three experiments address the dependence of both explicit and implicit memory performance on elaborative processes for a perceptual-motor task, pursuit rotor. Explicit memory performance was reflected by recognition of previously encountered pursuit rotor stimuli. Implicit memory performance (priming) was identified in Experiment 1 as an advantage in pursuit rotor performance for old stimuli that Ss failed to explicitly recognize. In Experiments 2 and 3, the types of strategies that Ss engaged in during training and test phases were manipulated. Results indicated that explicit memory performance depended on elaborative processes that emphasized which specific stimuli were encountered, whereas reliable implicit memory performance appeared only under a control no-instruction condition. Discussion focuses on attention to perceptual-integrative processes for priming.

title: Practice schedule effects on the performance and learning of low- and high-skilled students: an applied study.
abstract: This study examined the effects of practice schedule manipulations implemented in an instructional setting on the performance and learning of low- and high-skilled students. College undergraduates (N = 83) enrolled in 5 tennis classes completed a pretest on the forehand and backhand ground strokes, practiced these skills under a blocked or alternating schedule, and then completed a posttest. Results indicated that practice schedule effects on learning were influenced by student ability. Low-skilled students assigned to the blocked schedule had higher posttest scores than those assigned to the alternating schedule, whereas no significant differences were found for high-skilled students. These findings are discussed in relation to previous applied and laboratory-based findings and as a means for manipulating practice difficulty in teaching physical education.

title: Challenge Point: A Framework for Conceptualizing the Effects of Various Practice Conditions in Motor Learning
abstract: The authors describe the effects of practice conditions in motor learning (e.g., contextual interference, knowledge of results) within the constraints of 2 experimental variables: skill level and task difficulty. They use a research framework to conceptualize the interaction of those variables on the basis of concepts from information theory and information processing. The fundamental idea is that motor tasks represent different challenges for performers of different abilities. The authors propose that learning is related to the information arising from performance, which should be optimized along functions relating the difficulty of the task to the skill level of the performer. Specific testable hypotheses arising from the framework are also described.

title: Self-efficacy: Toward a unifying theory of behavioral change☆☆☆
abstract: The present article presents an integrative theoretical framework to explain and to predict psychological changes achieved by different modes of treatment. This theory states that psychological procedures, whatever their form, alter the level and strength of self-efficacy. It is hypothesized that expectations of personal efficacy determine whether coping behavior will be initiated, how much effort will be expended, and how long it will be sustained in the face of obstacles and aversive experiences. Persistence in activities that are subjectively threatening but in fact relatively safe produces, through experiences of mastery, further enhancement of self-efficacy and corresponding reductions in defensive behavior. In the proposed model, expectations of personal efficacy are derived from four principal sources of information: performance accomplishments, vicarious experience, verbal persuasion, and physiological states. The more dependable the experiential sources, the greater are the changes in perceived selfefficacy. A number of factors are identified as influencing the cognitive processing of efficacy information arising from enactive, vicarious, exhortative, and emotive sources. The differential power of diverse therapeutic procedures is analyzed in terms of the postulated cognitive mechanism of operation. Findings are reported from microanalyses of enactive, vicarious, and emotive modes of treatment that support the hypothesized relationship between perceived self-efficacy and behavioral changes. Possible directions for further research are discussed.

title: Contextual Interference and Motor Skill Learning in Alzheimer’s Disease
abstract: This study examined the acquisition, retention, and transfer of a gross motor skill, namely, tossing, in 84 moderate-to-severely demented patients with Alzheimer’s disease (AD) and 72 healthy elderly controls. To identify optimal learning strategies, participants received 10 weeks of training under 1 of 5 practice conditions: constant, variable-parameter, variable-program, variable-combined, or no training. Constant practice was the only training condition that significantly enhanced learning and near transfer in AD patients. In comparison, all 4 types of training facilitated acquisition and near transfer in the healthy controls, with variable-combined practice being the most beneficial. The superiority of the variable practice conditions in the healthy controls supports both Schmidt’s (1975) variability of practice hypothesis and contextual interference theory. The inability of AD patients to benefit from variable forms of practice suggests that these impaired individuals may have difficulty accessing and/or forming motor schemas.

title: Facilitating acquisition and transfer of a continuous motor task in healthy older adults and patients with Alzheimer's disease.
abstract: This study examined the acquisition and transfer of a fine motor skill, namely the rotary pursuit, in 99 patients with Alzheimer's disease (AD) and 100 normal controls (NCs). To identify optimal learning strategies, the authors had participants practice the rotary pursuit under constant, blocked, random, or no training conditions. Transfer was assessed using speeds that were different from those practiced during acquisition. AD patients and NCs receiving constant practice outperformed their peers in the blocked and random conditions during acquisition. Whereas all 3 types of practice facilitated transfer in the NCs, AD patients only benefited from constant practice. The inability of the AD patients to benefit from variable practice suggests that these individuals may have difficulty accessing and/or forming motor schemas.

title: The Variability of Practice Hypothesis in Motor Learning: Does It Apply to Alzheimer's Disease?
abstract: Based on Schmidt's (1975) variability of practice hypothesis, this study examined acquisition and transfer of a gross motor skill, namely tossing, in 58 patients with Alzheimer's disease (AD) and 58 healthy older adults under constant, blocked, and random practice conditions. While healthy older adults were able to learn the tossing task equally well under the three practice conditions, only AD patients receiving constant practice showed significant improvements. Tests of intermediate transfer yielded the expected random practice advantage in healthy controls but not AD patients. None of the practice conditions facilitated intermediate transfer in AD patients; however, constant practice did benefit these impaired individuals on tests of near transfer. These results indicate that the variability of practice hypothesis does not extend to AD patients. As motor learning and transfer were clearly a function of constant practice, future attempts to retrain basic activities of daily living in AD patients should emphasize consistency in training.

title: Acquisition and long-term retention of a gross motor skill in Alzheimer's disease patients under constant and varied practice conditions.
abstract: This study examined the acquisition and long-term retention of a gross motor skill, namely, tossing, in 23 moderately to severely demented Alzheimer's disease (AD) patients and 22 health older adults. To identify optimal learning strategies, subjects received 10 weeks of training under either constant or variable practice conditions. Accuracy at the tossing task was assessed immediately, one week, and one month following training. AD patients given constant practice were able to learn and retain the tossing task as well as healthy adults. Although controls performed equally well in both conditions, AD patients showed significantly less improvement when practiced at various distances from the target. By the one-month post-test, these patients had lost any minimal gains achieved through practice. In comparison, AD patients receiving constant practice showed essentially no forgetting across post-tests. The inability to benefit from varied practice suggests that AD patients may have difficulty accessing and/or forming motor schemas.

title: Procedural memory in Parkinson's disease: impaired motor but not visuoperceptual learning.
abstract: A current model proposes that memory consists of two functionally separate systems that have different neurological substrates. Declarative memory appears to be dependent on the diencephalic medial temporal lobe system whereas some speculate that the basal ganglia may be a neurological substrate for procedural memory. This study tested the role of the basal ganglia in regulating different types of procedural skills by comparing performance on a motor and a visuoperceptual skill learning task. Twenty Parkinson's (PD) patients and 20 normal control subjects performed two procedural learning tasks (rotary pursuit and mirror reading) and one declarative learning task (paired associates) over 3 days. The results showed that PD patients were not impaired on mirror reading or paired associate learning. On rotary pursuit, performance levels on day 1 were similar between groups, but the PD group showed less improvement across days than controls. However, only patients with more advanced symptoms of PD showed impaired rotary pursuit learning, and this could not be attributed directly to deficits in primary motor or general cognitive function. These findings suggest that the underlying processes/procedures for procedural learning are specific to the task, and are supported by different neuroanatomical systems.

title: Spacing effects and their implications for theory and practice
abstract: There is considerable evidence, gathered in a variety of settings and across many different types of materials and procedures, that spaced repetitions—regardless of whether they are in the form of additional study opportunities or successful tests—are a highly effective means of promoting learning. Research on spacing effects is reviewed and its theoretical and educational implications are examined. It is concluded that spacing effects can best be understood in terms of the “accessibility” hypothesis, and that spaced repetitions have considerable potential for improving classroom learning.

title: Neurogenesis and the spacing effect: learning over time enhances memory and the survival of new neurons.
abstract: Information that is spaced over time is better remembered than the same amount of information massed together. This phenomenon, known as the spacing effect, was explored with respect to its effect on learning and neurogenesis in the adult dentate gyrus of the hippocampal formation. Because the cells are generated over time and because learning enhances their survival, we hypothesized that training with spaced trials would rescue more new neurons from death than the same number of massed trials. In the first experiment, animals trained with spaced trials in the Morris water maze outperformed animals trained with massed trials, but there was not a direct effect of trial spacing on cell survival. Rather, animals that learned well retained more cells than animals that did not learn or learned poorly. Moreover, performance during acquisition correlated with the number of cells remaining in the dentate gyrus after training. In the second experiment, the time between blocks of trials was increased. Consequently, animals trained with spaced trials performed as well as those trained with massed, but remembered the location better two weeks later. The strength of that memory correlated with the number of new cells remaining in the hippocampus. Together, these data indicate that learning, and not mere exposure to training, enhances the survival of cells that are generated 1 wk before training. They also indicate that learning over an extended period of time induces a more persistent memory, which then relates to the number of cells that reside in the hippocampus.

title: Feedback-Induced Variability and the Learning of Generalized Motor Programs.
abstract: As compared with providing extrinsic feedback on each of a set of practice trials, reducing the feedback frequency in various ways facilitates long-term retention. One explanation is that frequent feedback operates proactively on the subsequent trial, inducing excessive variability that degrades learning. We tested this view by giving or not giving feedback "reminders," where the postresponse feedback was given again just before the next attempt at a task. The reminder manipulation was examined in both blocked and randomized practice sequences during the learning of three limb-patterning tasks. Reminder feedback increased response variability during practice in both random and blocked practice. As measured in retention tests, though, feedback reminders degraded learning in random practice, but not in blocked practice. This implies that the frequently found learning advantages of random, as compared with blocked, practice might be due to feedback's facilitation of retrieval operations in blocked practice (as well as in random practice with feedback reminders); such overfacilitation of retrieval operations has been shown to degrade learning. Additional analyses revealed that random, as compared with blocked, practice enhanced the learning of the fundamental pattern of action (generalized motor program) but had little effect on the ability to scale the pattern in amplitude or time (parameterization).

title: Interlimb coordination: Learning and transfer under different feedback conditions
abstract: The role of intrinsic and extrinsic information feedback in learning a new bimanual coordination pattern was investigated. The pattern required continuous flexion-extension movements of the upper limbs with a 90 ° phase offset. Separate groups practiced the task under one of the following visual feedback conditions: (a) blindfolded (reduced FB group), (b) with normal vision (normal FB group), or (c) with concurrent relative motion information (enhanced FB group). All groups were subjected to three different transfer test conditions at regular intervals during practice. These tests included reduced, normal vision, and enhanced vision conditions. Experiment 1 showed that the group receiving augmented information feedback about its relative motions in real-time produced the required coordination pattern more successfully than the remaining two groups, irrespective of the transfer conditions under which performance was evaluated. Experiment 2 replicated and extended the superiority of the enhanced feedback group during acquisition and retention. Experiment 3 demonstrated that successful transfer to various transfer test conditions was not a result of test-trial effects. Overall, the data suggest that the conditions that optimized performance of the coordination pattern during acquisition also optimized transfer performance.

title: Learning, Retention and Generalization of a Mirror Tracing Skill in Alzheimer's Disease
abstract: The present study examined the ability of 12 patients with probable Alzheimer's disease (AD) and 12 age- and education-matched normal control (NC) subjects to learn and retain the visuomotor skills necessary to efficiently trace a pattern (e.g., a 4- or 6-pointed star) seen only in mirror-reversed view. Those AD (N =6) and NC (N =7) subjects who were able to initially perform the basic mirror tracing task did not differ significantly in initial level of performance, learning over trials, retention of the skill over a 30-min delay interval, and generalization of the skill to a new figure or to the opposite direction of tracing. The AD patients who were unable to initially perform the mirror tracing task were significantly worse than those who could perform the task on several neuropsychological measures sensitive to deficits in problem solving and executive functions, but not on tests of global cognitive decline, memory, language, or visuoperceptual functioning. These results indicate that acquisition and retention of a complex visuomotor skill can proceed normally in the early stages of AD in those individuals who can initially perform the basic task, and that inability to perform the basic task may be related to the frontal lobe dysfunction that is often prominent in the disorder.

title: Implicit and Explicit Memory Following Anterior Communicating Artery Aneurysm Rupture
abstract: Several tasks examined the status of implicit and explicit memory in three patients with a ruptured anterior communicating artery (ACoA) aneurysm, one patient with bilateral temporal lobe damage sustained from herpes encephalitis (HE), 12 Alzheimer's disease (AD) patients, and 16 elderly normal controls demographically matched to the AD patients. All subjects completed word stem-completion repetition priming, pursuit-rotor tracking, and a fragmented pictures test, followed by explicit memory tests. ACoA, HE, and AD patients were impaired on all explicit tests. HE and AD patients were impaired on stem-completion priming, but were intact on other implicit tests. ACoA patients were intact on all implicit tests given. Discussion of these results considers similarities and differences in extent of basal forebrain and temporal lobe damage.

title: Acquisition and Long-Term Retention of a Fine Motor Skill in Alzheimers-Disease
abstract: This study investigated the acquisition and long-term retention of the rotary pursuit task under varying amounts of practice in 12 moderate-to-severely demented AD patients and 12 healthy older adults. Equal numbers of AD and control subjects were randomly assigned to either 40, 80, or 120 trials of training (40 trials/day) on the rotary pursuit task, followed by 15-trial retention tests 20 min, 2 days, 7 days, and 37 days following the end of practice. Performance improved significantly in both groups during the first 40 trials, while additional practice provided no ensuing positive or negative effects. Further, subjects in both groups showed minimal forgetting across the four retention tests. Therefore, the results demonstrated that AD patients can effectively learn and retain a motor skill for at least 1 month.

title: Preserved motor learning in Alzheimer's disease: implications for anatomy and behavior
abstract: Learning and retention of 3 types of information were examined in patients with Alzheimer's disease (AD) and in normal controls. While patients were unable to learn series of frequent words and unfamiliar faces, they improved significantly in a motor skill, showing a learning curve similar to controls. Furthermore, no significant loss of the motor skill was evident in a 20 min delay trial. Such dissociation in learning has not been noted previously in AD, although it has been noted in amnesias caused by other disease processes. The results support the existence of two, relatively independent, learning systems related to “declarative” knowledge and “procedural” knowledge. Judging from the pathologic correlates of these amnesias, the declarative knowledge system appears to be associated with corticotemporo/limbic structures, while the procedural system is likely to depend on corticocerebellar/striatal structures. The data also offer additional cognitive correlates for the selective damage to neural systems recently identified in AD.

title: Impaired learning of a motor skill in patients with Huntington's disease.
abstract: The ability of patients with Huntington's disease (HD), patients with dementia of the Alzheimer's type (DAT), and amnesic patients (AMN) to acquire the motor skills underlying a pursuit rotor task was assessed. Differences between groups in initial levels of performance were minimized by adjusting the rotation speed of the disk. The HD and DAT groups were also administered a verbal recognition span test. The results showed that the DAT, AMN, and intact control groups all significantly improved their time on target over six test blocks whereas the HD group was severely impaired in the acquisition of this motor skill. On the verbal recognition span test, the DAT and HD groups were significantly and equally impaired, but the HD group evidenced better immediate and delayed recall than did the DAT group. These results provide further evidence that the basal ganglia are critically involved in the acquisition of motor skills.

title: Neuropsychological evidence for multiple implicit memory systems: a comparison of Alzheimer's, Huntington's, and Parkinson's disease patients
abstract: The performances of patients with dementia of the Alzheimer type (DAT), patients with Huntington's disease (HD), and demented and nondemented patients with Parkinson's disease (PD) were compared on 2 tests of implicit memory that do not require the conscious recollection of prior study episodes: (1) a pursuit-rotor motor learning task and (2) a lexical priming test. The HD patients were found to be impaired on the motor learning but not the lexical priming task, whereas the DAT patients evidenced the opposite relationship on these tasks. The demented, but not the nondemented, PD patients were found to be impaired on both tests of implicit memory. For both the HD and PD patients, deficits on the motor learning task correlated significantly with severity of dementia but not with level of primary motor dysfunction. The noted double dissociation between HD and DAT patients indicates that different forms of implicit memory, all of which are intact in amnesia, are dependent upon distinct neuroanatomic systems. Motor skill learning may be mediated by a corticostriatal system, whereas verbal priming may depend upon the integrity of the neocortical association areas involved in the storage of semantic knowledge. The results for the PD patients suggest that the demented PD patients have endured damage to the neurologic systems subserving both motor learning and lexical priming.

title: Declarative and procedural learning, quantitative measures of the hippocampus, and subcortical white alterations in Alzheimer's disease and ischaemic vascular dementia.
abstract: This research investigated whether subjects with Alzheimer's disease (AD) and ischaemic vascular dementia (IVD) associated with periventricular and deep white matter alterations can be dissociated on tests of declarative and procedural memory, as well as on MRI indices of white matter alterations and the size of the hippocampal formation. The California Verbal Learning Test (CVLT) and the Pursuit Rotor Learning Tests (PRLT) were used to measure declarative and procedural memory, respectively. Subjects with IVD obtained a higher score on the CVLT recognition discriminability index; however, on the PRLT total time on target, carry-over between trial blocks, and slope calculated for all test trials was low. Subjects with AD exhibited the opposite profile. MRI studies indicated that subjects with IVD had considerably greater white matter alterations, but larger hippocampal formations than subjects with AD. Higher scores on the CVLT recognition discriminability index were correlated with increased size of the body of the hippocampus and parahippocampal gyrus. By contrast, as the severity of white matter alterations increased the slope on the PRLT declined. In sum, subjects with AD and IVD can be dissociated on the basis of differing patterns of impairment on tests of declarative and procedural memory, and MRI indices of white matter alteration and the integrity of the hippocampal formation.

title: Procedural memory in patients with mild Alzheimer's disease.
abstract: Motor, perceptual, and cognitive skill learning abilities of mild Alzheimer's disease (AD) patients were compared to sex-, age-, and education-matched controls. We excluded patients who were unable to perform each skill learning task with a predetermined criterion. In those who completed the task, skill learning was as good as in normal controls. On the cognitive and perceptual skill learnings, some of the AD patients, whose cognitive but not declarative memory functions were more severely impaired than in those who completed the whole session, failed to complete the task, while all patients could complete the motor task. These results support that view that patients with mild AD can acquire motor, perceptual, and cognitive skills and that the neural system subserving procedural skill is not related to the neural systems for declarative memory.

title: Implicit learning in patients with probable Alzheimer's disease
abstract: The purpose of the present study was to determine whether patients with probable Alzheimer's disease (AD) were capable of implicit procedural learning. AD patients and elderly control subjects were given a serial visual reaction time task with an embedded repeating sequence. The AD patients responded more slowly than the controls, but many nonetheless showed learning of the repeating sequence. Patients who failed to learn the sequence were similar in age and overall severity of dementia to those who learned, but they scored lower on some tasks of nonverbal reasoning.

title: Intact acquisition and long-term retention of mirror-tracing skill in Alzheimer's disease and in global amnesia.
abstract: The ability of patients with Alzheimer's disease (AD) or global amnesia (AMN) to acquire skill for tracing a pattern seen in mirror-reversed view and to retain that skill over 24-h intervals was examined. Both patient groups had poor recall and recognition of their mirror-tracing experience, but they acquired and retained mirror-tracing skill as well as normal control subjects. One AMN patient (H.M.) retained the skill over a year-long interval. Furthermore, the patients transferred their skill normally to an alternate pattern. These results indicate that the memory system underlying mirror-tracing skill learning is separable from medial-temporal structures compromised in AMN and AD and from neocortical areas compromised in AD. Brain regions relatively spared in early AD, such as the basal ganglia or cerebellum, may mediate critical aspects of the learning of novel sensorimotor associations that underlie skilled mirror tracing.

title: The role of examples and rules in the acquisition of a cognitive skill.
abstract: In 3 experiments, participants memorized 8 examples, each exemplifying a different rule. Participants were asked to extend these rules to new examples. They practiced applications of the rules to examples over a period of 4 days (Experiment 1) or 5 days (Experiments 2 and 3). Although these rules were bidirectional, an asymmetry gradually built up such that participants became more facile in using the rules in the practiced direction. Participants also showed an advantage when the initial study example was repeated or when test examples were repeated. It is argued that skill acquisition involves development of a complex set of strategies based on use of rules and retrieval of examples. Four overlapping stages of skill acquisition are described.