Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Richard A. Magill


The experiments reported here were designed to test a hypothesis regarding why the contextual interference (CI) effect in retention of motor skills occurs. It was hypothesized that the high-CI or random group performs better on a retention test than the low-CI or blocked group because the random schedule has included practice in retrieving motor tasks from long-term memory (LTM). This is the same information-processing activity required for successful retention test performance. In essence, both groups learn the motor task to the same extent, but the random group also learns to recall the task from LTM on demand. In the first experiment, groups were given either a high number of opportunities during practice to retrieve tasks from LTM (random schedule), an intermediate number (modified-blocked schedule), or no opportunities (blocked schedule). On a retention test, the groups given opportunities to retrieve tasks from LTM during practice performed significantly better than the group given no opportunities. In the second experiment, blocked and random schedules were again tested, but the task was changed so that both schedules offered no opportunity for retrieval of tasks from LTM. No differences in retention between groups were expected in this case, and none were found. These experiments provided support for the idea that CI in motor learning benefits retention only when the practice schedule forces subjects to retrieve tasks from LTM during practice trials.