It is believed that when inter-trial time is not controlled, the CI effect will occur (i.e., random practice will outperform blocked practice in retention), and random practice will take longer to perform (inter-trial and overall timing) than blocked practice. However, when inter-trial time is kept constant, it is expected that the benefits of random practice will no longer be present (i.e., no CI effect). Providing a consistent inter-trial time is expected to diminish the CI effect because random practice groups will no longer have the advantage of extended cognitive processing. What are the Effects of Inter-Trial Timing on Contextual Interference? Andrea M. Courtnier and Natalie L. Thomas – Department of Exercise Science, Pacific University Faculty Advisor: Brian H. Jackson, Ph.D. 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). Background Methods 60 volunteers from the Pacific University community will serve as participants. Participants will be tasked with learning/performing three different sequences of a key-press task. Using their dominant hand index finger, participants will press five buttons in a specific sequence as fast and accurately as possible. The three patterns will be associated with a specific color (red, yellow, blue) for retention purposes, and will be performed 30 times each (90 total acquisition trials). Cues for the trials to begin will be signaled by the color of the pattern and pattern sequence displayed on the monitor. One second after participants finish the key pattern, feedback will be provided (accuracy & timing). 1.Lee, TD; Wishart, LR; Cunningham, S; & Carnahan, H (1997). Modeled timing information during random practice eliminates the contextual interference effect. Research Quarterly for Exercise and Sport, 68 (1), Lin, CJ; Fisher, BE; Winstein, CJ; Wu, AD; & Gordon, J (2008). Contextual interference effect: Elaborate processing or forgetting re- construction? A post hoc analysis of transcranial magnetic stimulation- induced effects on motor learning. Journal of Motor Behavior, 40 (6), Shea, JB & Morgan, RL (1979). Contextual interference effects on the acquisition, retention, and transfer of a motor skill. Journal of Experimental Psychology: Learning, Memory, and Cognition, 27, Simon, DA (2007). Contextual interference effects with two tasks. Perceptual and Motor Skills, 105, For each trial, performance time (time from the start of the sequence to the end of the sequence) and accuracy (correct sequence or not) will be recorded. In addition, for the conditions without a time-constraint, inter-trial time (time from delivery of the sequence to the beginning of the performance) and total time (time to complete practice session) will be gathered. A 2x2x2 (Schedule X Time Constraint X Time) repeated-measures ANOVA will be performed for each of the dependent variables (speed and accuracy) to determine group differences in the short- and long- term retention tests. Data Analyses Purpose Hypotheses 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). By replicating research by Lee and colleagues (1997), the proposed study has three distinct purposes: 1. Further explore the contextual interference effect and determine if random practice in indeed more beneficial than blocked practice in learning. A blocked and random practice schedule will be compared in acquisition and retention. 2. Determine whether random practice naturally takes longer to perform than blocked practice. The inter-trial and total practice time of the random and blocked practice schedules will be gathered during self- paced practice. 3. Determine whether the benefits of random practice will be minimized or removed when inter-trial time is controlled. Blocked and random practice schedules will be compared while practicing with the same inter-trial pacing. Participants will be grouped based on: Time Constraint No time constraint- Participants will press a start button when they feel they are ready to begin the pattern displayed. Time constraint- Participants must begin the sequence when the word “Go” appears on the screen (5 seconds following the presentation of the sequence). Participants will perform two identical retention tests. In each, participants will perform 10 trials of each pattern in a random order without feedback. There will be no time constraint. Short-Term Retention : 3 minutes following completion of the acquisition period. Long-Term Retention : 24 hours following completion of the acquisition period. Upon IRB approval (pending), data will be collected and analyzed by March Conclusions will be made and disseminated by May Timing Selected References Figure 1. DirectIN High Speed Button Box Practice Schedule Blocked- 30 trials of one pattern will be performed before moving on to the next sequence. Random- 30 trials of each pattern will be performed in an unpredicted order.