in many learning domains, varied practice has been shown to enhance the retention, generalization and application of acquired skills. there are many potential sources of the observed advantages. first, greater diversity of the tasks may also allow the learner to extract the most relevant, task-invariant information. any given practice trial contains both task-relevant and task-irrelevant information. by mixing up the trials, task-irrelevant information will be less consistent, allowing the learner to strip away the spurious associations. task-relevant information should be constant regardless of the particulars of individual trial.