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What are the Effects of Inter-Trial Variation on Contextual Interference?

16 November 2010


Contextual Interference (CI) is the observed effect that occurs when numerous tasks are randomly organized within the same practice session (Shea & Morgan, 1979). Research has shown that practicing tasks in a random schedule (e.g. C, A, B, A, C, B) leads to greater long-term learning of a skill when compared to a blocked schedule (e.g. A, A, B, B, C, C). Although a blocked schedule has been found to improve performance in the acquisition of a motor skill, those who practice under a random schedule demonstrate superior leaning in the retention and transfer of the task (Simon, 1997). There are numerous explanations as to why this effect (CI Effect) occurs, but the most popular is the Action-Plan Reconstruction Hypothesis (i.e., Forgetting Hypothesis). This hypothesis suggests that changing from one skill to another randomly during a practice session forces the learner to reconstruct the skills various action plans over and over, eventually leading to a stronger memory representation of a skill, and higher performances on retention and transfer tasks (Lin et al, 2008).

If the Forgetting Hypothesis is true, and learning in a random schedule will require more cognitive effort to “forget” and ‘remember” the skill, it would seem that switching between tasks more often would take more time than practicing blocked sets of the same skill. This natural spacing between trials (i.e., time needed to cognitively recall the skill) could naturally lead to random practice groups having more time to cognitively engage in the tasks. If so, the extra time used to process the skill may be the actual benefit of random practice, and in fact lead to the CI effect (Lee et al, 1997).


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