Course:KIN366/ConceptLibrary/Contextual Interference

From UBC Wiki
Jump to: navigation, search
Movement Experiences for Children
Wiki.png
KIN 366
Section:
Instructor: Dr. Shannon S.D. Bredin
Email: shannon.bredin@ubc.ca
Office:
Office Hours:
Class Schedule:
Classroom:
Important Course Pages
Syllabus
Lecture Notes
Assignments
Course Discussion

Coaches and physical educators are well aware that the amount of practice a young athlete receives can greatly improve their performance in competition but the quality and structure of practice can arguably have just as great an effect on performance. Repetition of skills is often a key feature in practice; it is a common belief that the more times you repeat a certain skill the better it will become engrained in your body as if the movement pattern is somehow imprinted into your system. But does repeating the same skill over and over again really lead to the best performance later on? Do athletes sometimes perform well in practice but fall apart in a game or competition? The structure of individual practice sessions not only affects the athletes’ performance in practice but also in competition and constantly varying game situations. It can be useful for coaches to understand how manipulating contextual interference during practice can maximize the learning of each young athlete.

Contextual Interference

Coker (2009) defines contextual interference as the interference that results from switching from one skill to another or changing the context in which the task is practiced from trial to trial. The amount of interference in between tasks can range from low, where a task is practiced by itself, to high, where a number of skills are practiced together. Changes in context can include performing the same task from different angles or distances.


The Contextual Interference Effect is the phenomenon that arises from experiments comparing the effects of random- and blocked-practice schedules on the learning of several tasks. Although blocked practice produces better performance than random practice during initial rehearsal but when performance is compared on later retention tests random practice produces better learning than blocked practice (Schmidt & Wrisberg, 2000).

Types Of Practice Schedule

Blocked

Blocked-schedule practices provide low contextual interference. Skills are practiced in a repetitive pattern and one skill is practiced at a time. Take, for example, a basketball practice dedicated to practicing three different skills: bounce pass, chest pass, and overhead pass. In a blocked practice all trials of the bounce pass would be performed first, followed by all trials of the chest pass and finally all trials of the overhead pass.

Bounce Pass Bounce Pass Bounce Pass Bounce Pass Bounce Pass
Bounce Pass Bounce Pass Bounce Pass Bounce Pass Bounce Pass
Chest Pass Chest Pass Chest Pass Chest Pass Chest Pass
Chest Pass Chest Pass Chest Pass Chest Pass Chest Pass
Overhead Pass Overhead Pass Overhead Pass Overhead Pass Overhead Pass
Overhead Pass Overhead Pass Overhead Pass Overhead Pass Overhead Pass

Random

Random-schedule practices provide high contextual interference where skills are practiced in a random order. Some researchers create random schedules in which no tasks are performed twice in a row and other researchers allow tasks to be practiced twice in a row before switching. In a basketball practice where the skills of bounce pass, chest pass, and overhead pass are to be practiced a sample schedule might look like this:

Overhead Pass Bounce Pass Chest Pass Bounce Pass Chest Pass
Bounce Pass Overhead Pass Chest Pass Overhead Pass Bounce Pass
Chest Pass Bounce Pass Overhead Pass Chest Pass Overhead Pass
Chest Pass Overhead Pass Bounce Pass Overhead Pass Bounce Pass
Overhead Pass Chest Pass Bounce Pass Chest Pass Bounce Pass
Bounce Pass Chest Pass Overhead Pass Chest Pass Overhead Pass

Serial

Serial practice schedules are considered to have medium levels of contextual interference. No skill is practiced repetitively but the order of all three trials shows a blocked pattern. In a basketball practice where the skills of bounce pass, chest pass, and overhead pass are to be practiced a sample schedule might look like this:

Bounce Pass Chest Pass Overhead Pass Bounce Pass Chest Pass Overhead Pass
Bounce Pass Chest Pass Overhead Pass Bounce Pass Chest Pass Overhead Pass
Bounce Pass Chest Pass Overhead Pass Bounce Pass Chest Pass Overhead Pass
Bounce Pass Chest Pass Overhead Pass Bounce Pass Chest Pass Overhead Pass
Bounce Pass Chest Pass Overhead Pass Bounce Pass Chest Pass Overhead Pass

Research in Contextual Interference

The Research Design

Most research studies examining the contextual interference effect follow a similar protocol. Participants are normally required to learn three new movement skills although in some studies this number can vary from two to six. These skills range from sport specific skills such as baseball pitches to simple skills such as pressing buttons on a keyboard in a specific pattern. Participants are given a pre-test to determine baseline performance and are then randomly placed into groups and given the task of practicing in either a blocked schedule or a random schedule during the acquisition phase. Each group completes the same number of trials and performance is measured at the end of this phase to see how much they have improved over time.


To determine whether the participants have created a permanent change and truly learned the skill they are asked to perform a retention test. This is different from the post-test, which is completed immediately after practice session. A retention test is administered after a period of time during which the learner has not practiced the skill. The amount of time between the end of practice and the retention test will vary amongst studies and can range from a few minutes to over a week. If the participant’s score remains high they have learned this new skill and the method of practice was successful but if the score is significantly lower then it can be said that the method of practice did not help learning. The goal of the retention test in contextual interference research is to compare the amount of learning between practice schedules.


The researchers will then include a transfer test. This will be a new test for a task that no one has had experience with in practice. This may be a skill that is similar to the previous task such as a baseball pitch made from a new angle or it may be more complex such as a pattern of keyboard button presses that is much longer than the original. Ollis et al. (2005) suggest that the transfer test is an indicator of the adaptability of performance and is the best representation of the flexibility a learner may need to employ in a real-life situation.

Early Research

Shea and Morgan (1979) conducted an early study on the effects of practice schedule on the acquisition, retention, and transfer of motor skills. Participants in this study were asked to knock down wooden pegs in three different patterns as fast as possible. Half of the participants practiced using a blocked schedule and the other half practiced using a random practice schedule. During the initial practice the blocked group improved significantly faster than the random group. The random group improved at a much slower rate but by the end of the practice period performance for both groups had similar levels of performance. In retention tests the blocked-practice schedule group did not retain their level of performance and were significantly slower than the random-practice schedule group in both blocked and random conditions. Participants were then asked to perform a new pattern at the same level of difficulty and a more complex pattern. Results were the same as retention tests and the random-practice schedule group outperformed the blocked-practice schedule group.

Explaining the Contextual Interference Effect

There are two main hypotheses that try to explain why random-practice conditions lead to better learning and transfer than blocked-practice conditions: the elaboration hypothesis and the forgetting hypothesis.


The elaboration hypothesis proposes that learners are able to appreciate the differences between tasks by comparing and contrasting movements. When performing tasks in random order learners may find similarities and differences in the varied movements that allow them to create more meaningful and distinctive memories of the movements. Blocked practice may not easily allow for these comparisons between movements because they are never performed one after the other (Schmidt & Wrisberg, 2000).


The forgetting hypothesis suggests that when switching from one task to another the learner forgets what they did on the first task while they are planning the second task. Thus, when they are asked to perform the first task again they must create a new plan of action. Blocked practice would not require the learner to create a new action plan every time they performed a task but only the first time and they would then automatically perform the same task with the same plan. Schmidt and Wrisberg (2000) point out that practicing the retrieval of these action plans is a skill that can be applied to a more realistic setting such as a game or competition where tasks are not performed in a blocked fashion.

Sport-Specific Research

A number of studies have been conducted on sport-specific skills and contextual interference but the results vary amongst studies (Brady, 2004). In a study conducted with skilled college baseball players, Hall et al. (1994) examined the effects of schedule in extra batting practices in addition to regular team training. The random practice group improved their performance to a greater degree than the blocked practice group and the blocked practice group improved more than the control group that had no extra batting practice. Goode and Magill (1986) studied the effects of blocked, random, and serial practice schedules on three different badminton serves using novice learners. The authors found the presence of the contextual interference effect with the random practice group performing better on retention and transfer than the serial- and blocked-practice groups. The serial-practice group also displayed greater learning than the blocked-practice group. Bertollo et al. (2010) examined the effect of practice schedule on the learning and retention of rhythmic dance patterns and did not find any differences in retention among the blocked group and random group learners. Manipulations of contextual interference in sport settings have produced varying results and show that laboratory findings of the contextual interference effect may not generalize well to applied settings.

Beyond Blocked and Random Schedules

Every learner is different and depending on their stage of learning, the difficulty of the task and complexity of the task a blocked or random schedule alone may not be effective (Brady, 2008). It is also challenging for physical educators and coaches to employ a strictly random practice condition. Not all research has focused only on the effects of blocked vs. random practice and researchers believe that in the applied setting it is important to also consider the advantages of a practice schedule with medium level of contextual interference (Landin & Hebert, 1997). Landin and Hebert (1997) examined three practice schedules of six basketball shots from varying positions. In the medium contextual interference condition players completed three trials in each position before moving to the next position and repeated these short blocks in a serial pattern. Landin and Hebert (1997) found that the medium contextual interference group preformed better on retention tests than both a blocked group and a serial group.


Some researchers have also studied the effects of increasing the amount of contextual interference over the course of the practice phase beginning with low contextual interference during the first phase of acquisition, medium contextual interference in the next phase of acquisition, and finally high contextual interference in the last phase of acquisition (Magill & Porter, 2010). Initial research into this method has shown that increasing the amount of contextual interference during the acquisition phase of a new motor skill can have greater benefits on retention than both blocked and random schedules (Magill & Porter, 2010). Cheong (2012) did not find any evidence, however, that practice schedule affected the learning and retention when field hockey skills were practiced using five different schedules with varying levels of contextual interference suggesting that many other factors may be involved in learning sport specific skills.

Research on Children

Zetou et al. (2007) conducted a study using female participants with a mean age of twelve years and little to no experience in volleyball. The authors examined the effects of a blocked practice compared to a random practice schedule on the acquisition of three volleyball skills. While all participants improved over the practice phase during retention the authors did not find a significant difference between the two different practice schedules. The authors also suggest that the difficulty of the task combined with the inexperience of the learners may be the reason that there was no apparent contextual interference effect. This does not mean that the random practice was ineffective but that it produced the same amount of learning as blocked practice and at this age and skill level both types of practice could be used effectively to produce learning.


Saemi et al. (2012) compared the throwing accuracy from three different distances of male elementary students with a mean age of ten years. The students were not considered novices because they had previous experience with overhand throwing but were also not considered skilled throwers. The increasing contextual interference schedule group performed the first phase of trials in a blocked order, the second phase in a serial order, and the third phase in a random order similar to the study conducted by Porter and Magill (2010). In this study participants that followed a schedule of increasing contextual interference performed better than the blocked schedule group but not significantly better than the random schedule group (Saemi et al., 2012).


In a study comparing adults and children practicing the same simple task Pollock and Lee (1997) found that the contextual interference effect was present in transfer and retention for both children and adults but not in acquisition. While the adults showed the expected effect in acquisition phase with the blocked group performing better than the random group the performance level of the children was similar for both groups during acquisition. These findings are similar to those of other studies in children which suggest that during the acquisition phase both types of practice schedule could be employed when working with children (Zetou et al., 2007; Saemi et al., 2012).

Criticisms of Contextual Interference Research

Contemporary criticisms of the research on contextual interference point out that the effect is most widely seen in basic laboratory research but is less observed in real-life settings (Brady, 2008). This leads to questions about whether the difference between blocked and random schedules is significant enough to be taken in to consideration in a practical sports setting. The research on contextual interference in sport settings has been inconclusive so far with some studies reporting the benefits of random practice over blocked practice and other studies finding no differences in learning and performance (Brady, 2008).


Research has also shown that contextual interference can improve the performance of experienced learners to a greater degree than novice learners (Tsutsui, 2013). In a meta-analytic review Brady (2004) found the effect of manipulating contextual interference to be moderate in adults but relatively small in children; in other words, high contextual interference in children creates only a small difference in learning. Since this analysis was published there has been continuing research into the effects of systematically increasing contextual interference during practice in children and may prove to have beneficial results (Saemi et al., 2012).

When Should Random Practice Be Introduced?

Coaches and physical educators will have to take many variables into consideration when deciding whether to incorporate random practice with young athletes including the stage of learning, the task difficulty, and the target task and context for the specific sport.

Stages Of Learning

Fitts and Posner (1967) propose that learning a new skill occurs in three stages. In the Early or Cognitive Phase the learner is trying to understand the new movement and must pay attention to cues, events, and responses that will later go unnoticed. In the Intermediate or Associative Phase the amount of large errors the learner makes are slowly eliminated and separate components of the task that initially took individual attention are combined to form new patterns of movement. The last stage of learning is the Final or Autonomous Phase where the skill becomes automatic and less cognitive processing is required for completion. The learner is less affected by interference from other ongoing activities or environmental distractions and improvements in speed and efficiency continue.


A commonly used example of the stages of learning in a real life situation is learning to drive a car. When learning to drive a car for the first time a learner will have many things to focus on simultaneously such as turning the wheel while looking for pedestrians and checking the side view mirrors. Eventually, actions such as turning the wheel become more automatic and the driver does not have to devote as much attention to individual tasks. With practice, the driver is able to complete many tasks automatically and now treats driving as a single task rather than a combination of individual components that each need attention.


Landin and Hebert (1997) suggest that in the first stage of learning a new skill a task may prove to involve too much cognitive effort on behalf of the learner and may be negatively affected by high amounts of contextual interference. Magill and Porter (2010) and Saemi et al. (2012) suggest that a schedule of increasing contextual interference could help to overcome the challenges of learning a new task by providing blocked repetitions during the first stage of learning while the learner becomes familiar with the movement and then increasing the contextual interference once the learner has become more experienced. In this case the learner will still experience the benefits of high contextual interference but will not be hampered by them while they are still in the first stages of learning.


A coach or physical educator must be aware of what stage each young learner is in to determine whether a blocked, random, or increasing contextual interference schedule would be beneficial or detrimental.

Task Difficulty

Nominal difficulty is the fixed amount of difficulty a task has regardless of who is performing the task, for example a lowered basketball hoop would present a less difficult task for everyone than a higher basketball hoop. Functional difficulty is the relative difficulty of the task performed based on the skill of the performer and the conditions under which the task is being performed (Guadagnoli & Lee, 2004). An example of functional difficulty is the amount of experience a learner has with basketball free throws. Another way functional difficulty can be increased is through random-practice schedules that make each individual task harder to perform.


Based on these two types of difficulty Guadagnoli and Lee (2004) proposed the challenge point theory as a way of explaining why the contextual interference effect is not consistently found in the literature. The challenge point theory examines the interaction between nominal and functional difficulty to produce an optimal point where learning will occur. Brady (2008) argues that in many experiments the conditions of random practice may increase the difficulty of a task beyond the learner’s challenge point and that learning will not occur as readily in these situations.


A coach or physical educator must take both the inherent difficulty of a task and the relative difficulty based on the learner and environment into consideration when deciding whether to use random practice or blocked practice. Blocked practice may keep the difficulty low enough for young learners to produce successful movements but if the learners are skilled enough then a random practice may offer optimal difficulty and therefore better learning.

Target Task and Target Context

The target task is the task a learner is hoping to improve such as a shot in golf or the ability to keep a tennis ball in play. The target context is the environmental context in which the learner wants to be able to perform the practiced skill. One of the popular criticisms of blocked practice is that it doesn’t replicate a real-life situation but rather a repetitive robot-like way of performing (Schmidt & Wrisberg, 2000). There are, however, some sports where the environment stays relatively constant and skills are reproduced in a consistent manner such as archery or competitive gymnastics and in such cases a blocked practice may replicate the conditions of competition. Many team sports require the athlete to make quick decisions and perform skills under a wide variety of constantly changing conditions. The coach or physical educator must decide what the target task and target context are for the learner and build the practice schedule based around these goals.

Conclusions

A coach or physical educator may find that the motivation of the learner could decrease with random practice because improvements are less noticeable (Coker, 2009). Blocked practice can increase confidence in a learner’s ability to perform because improvements are seen immediately whereas a new learner might feel frustrated with random practice as improvements are slower to appear. It is important to remember that although performance does not seem to improve as quickly during random practice compared to blocked practice this does not mean that no learning is taking place. Practice schedules that offer increasing contextual interference may provide the benefits of both blocked- and random- schedule practices.


Among the most promising research in contextual interference right now is the idea of incorporating increasing amounts of contextual interference into practice. In the initial stage of learning a new skill the young athlete practices in a blocked-schedule to overcome the challenges associated with increased cognitive processing and the address need for the learner to become familiar with the movements. Once the learner is able to consistently produce a required movement the schedule can start increasing to a moderate level of contextual interference such as serial practice or smaller blocks of trials practiced in a serial or random pattern. In the later stages of practice the coach or physical educator could begin to introduce even higher levels of contextual interference through random practice. This would increase the cognitive load and cause the learner to engage in higher levels of problem solving associated with producing varied movements and eliminate any automatic processes the learner may employ in later stages of learning. The amount of time spent in each phase would depend on the speed at which the learner acquires a new skill and their level of experience. Individual capabilities should be taken into consideration when designing a program of increasing contextual interference.


Despite the fact that the research examining the effects of contextual interference on learning in children is limited the implications for coaches and physical educators are still valid. With the knowledge of how to manipulate contextual interference during practice, coaches and physical educators can make more informed decisions about which practice structure to employ for young learners based on the athlete’s stage of learning, the difficulty of the task, and the goals of the practice. While research on the contextual interference effect and the benefits of random-schedule practice compared to blocked-schedule practice in sport specific contexts is still inconclusive it can be argued that incorporating different practice schedules can still provide advantages to the athlete.

References

Brady, F. (2004). Contextual interference: A meta-analytic study. Perceptual and Motor Skills, 99(1), 116-126.


Brady, F. (2008). The contextual interference effect and sport skills. Perceptual and Motor Skills, 106(2), 461-472. doi:10.2466/PMS.106.2.461-472


Bertollo, M., Berchicci, M., Carraro, A., Comani, S., & Robazza, C. (2010). Blocked and random practice organization in the learning of rhythmic dance step sequences. Perceptual and Motor Skills, 110(1), 77-84.


Cheong, J. P. G., Lay, B., Grove, J. R., Medic, N., & Razman, R. (2012). Practicing field hockey skills along the contextual interference continuum: A comparison of five practice schedules. Journal of Sports Science & Medicine, 11(2), 304-311.


Coker, C. A. (2009). Motor learning & control for practitioners. Scottsdale, Ariz: Holcomb Hathaway, Publishers.


Fitts, P. M., & Posner, M. I. (1979). Human performance. Westport, Conn: Greenwood Press.


Goode, S., & Magill, R. A. (1986). Contextual interference effects in learning three badminton serves. Research quarterly for exercise and sport, 57(4), 308-314.


Hall, K. G., Domingues, D. A., & Cavazos, R. (1994). Contextual interference effects with skilled baseball players. Perceptual and Motor Skills, 78(3 Pt 1), 835-841. doi:10.2466/pms.1994.78.3.835


Landin, D., & Hebert, E. P. (1997). A comparison of three practice schedules along the contextual interference continuum. Research Quarterly for Exercise and Sport, 68(4), 357.


Magill, R., & Porter, J. (2010). Systematically increasing contextual interference is beneficial for learning sport skills. Journal of Sports Sciences, 28(12), 1277-1285. doi:10.1080/02640414.2010.502946


Ollis, S., Button, C., & Fairweather, M. (2005). The influence of professional expertise and task complexity upon the potency of the contextual interference effect. Acta Psychologica, 118(3), 229-244. doi:10.1016/j.actpsy.2004.08.003


Pollock, B. J., & Lee, T. D. (1997). Dissociated contextual interference effects in children and adults. Perceptual and Motor Skills, 84(3 Pt 1), 851-858. doi:10.2466/pms.1997.84.3.851


Schmidt, R. A., & Wrisberg, C. A. (2000). Motor learning and performance. Champaign, IL: Human Kinetics.


Shea, J. B., & Morgan, R. L. (1979). Contextual interference effects on the acquisition, retention, and transfer of a motor skill. Journal of Experimental Psychology: Human Learning and Memory, 5(2), 179-187.


Tsutsui, S., Satoh, M., & Yamamoto, K. (2013). Contextual interference modulated by pitcher skill level. International Journal of Sport and Health Science, 68-75 doi:10.5432/ijshs.201211


Zetou, E., Michalopoulou, M., Giazitzi, K., & Kioumourtzoglou, E. (2007). Contextual interference effects in learning volleyball skills. Perceptual and Motor Skills, 104(3 Pt 1), 995-1004. doi:10.2466/PMS.104.3.995-1004