Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Three experiments are reported that examined the possibility that the contextual interference effect in motor skill learning is a variation of a multiple trial spacing of repetitions effect. Specifically, the question why a non-spaced condition in a spacing of multiple trials motor learning paradigm has not produced predicted retention deficits. Subjects in all experiments learned to perform a simple motor skill in a criterion movement time. Experiments 1 and 2 examined why spacing of multiple trials did not produce expected retention performance benefits in previous spacing experiments. The results of Experiment 1 and 2 showed that the randomness of the practice schedule and difficulty of the task were not related to the lack of retention benefits. In Experiment 3 the question when retention performance deficits might occur was addressed. This experiment replicated the contextual interference effect reported in the literature and showed that this phenomenon may be uniquely different from the spacing of multiple trials effect. The results of this experiment suggest that the retention performance of subjects in the blocked control condition in the contextual interference paradigm may suffer from interference experienced during the acquisition trials. When the retention test is given seems to partially determine the subjects' performance. The consequences for a reconstruction hypothesis as an explanation of the contextual interference effect are also discussed.