When will bigger be (recalled) better? The influence of category size on JOLs depends on test format.

Although it is well known that organized lists of words (e.g., categories) are recalled better than unrelated lists, little research has examined whether participants can predict how categorical relatedness influences recall. In two experiments, participants studied lists of words that included items from big categories (12 items), small categories (4 items), and unrelated items, and provided immediate JOLs. In Experiment 1, free recall was highest for items from large categories and lowest for unrelated items. Importantly, participants were sensitive to the effects of category size on recall, with JOLs to items from big categories actually increasing over the study list. In Experiment 2, one group of participants was cued to recall all exemplars from the categories in a blocked manner, whereas the other group was cued in a random order. As expected, the random group did not show the recall benefit for big categories over small categories observed in free recall, while the blocked group did. Critically, the pattern of metacognitive judgments closely matched actual cued recall performance. Participants' JOLs were sensitive to the interaction between category size and output order, demonstrating a relatively sophisticated strategy that incorporates the interaction of multiple extrinsic cues in predicting recall.