Category similarity affects study choices in self-regulated learning.

During learning, interleaving exemplars from different categories (e.g., ABCBCACAB) rather than blocking by category (e.g., AAABBBCCC) often enhances inductive learning, especially when the categories are highly similar. However, when allowed to select their own study schedules, learners overwhelmingly tend to block rather than interleave. Category similarity has been shown to moderate the relative benefit of interleaved versus blocked study. We investigated whether learners were sensitive to category similarity when choosing exemplars for study, and whether these choices predicted their learning outcomes. In Experiment 1, learners interleaved more often when the categories were highly similar (difficult to discriminate from each other), compared with when similarity was low. In Experiment 2, learners were presented with two sets of categories to learn; categories within each set were similar to each other, but categories were dissimilar across sets. When learners chose to interleave, they tended to switch to a similar rather than dissimilar category. Importantly, learners' study choices predicted their subsequent categorization performance. Our findings suggest that learners are strategic in their search for commonalities within versus differences among categories and can regulate their study behaviors based on category similarity.