Address for Correspondence:

This study investigates whether the use of a spacing strategy absolutely improves final performance, even when the learner had chosen, metacognitively, to mass. After making judgments of learning, adult and child participants chose to mass or space their study of word pairs. However, a third of their choices were dishonored. That is, they were forced to mass after having chosen to space and forced to space after having chosen to mass. Results showed that the spacing effect obtained for both adults and children when choices were honored. However, using a spacing strategy when it was in disagreement with one’s own choice, or forced, did not enhance performance for the adults (Experiment 1). And although it was enhanced for the children (beyond massing strategies), the performance was not as good as that when the spacing decisions were self-chosen (Experiment 2). The data suggest that although spacing is an effective strategy for learning, it is not universal, particularly when the strategy was not chosen by the learner. In short, metacognitive control is often crucial and should be honored. Control and Spacing