The font size effect depends on inter-item relation.

The font size effect refers to the metacognitive illusion that larger fonts lead to higher judgments of learning (JOLs) but not better recall. Prior studies demonstrated robust JOL effects of font size under conditions of intra-item relation (i.e., cue-target relatedness within a word pair), even though intra-item relation is a more diagnostic cue than font size. However, it remains an open question whether the JOL effects of font size persist under conditions of inter-item relation (i.e., relations across items on a single-word list). In the current study, we examined the JOL and recall effects of font size when font size and inter-item relation were factorially manipulated in three JOL-recall experiments. Additionally, to manipulate the salience of inter-item relation, we presented related and unrelated lists in a blocked manner in Experiment 1 but in a mixed manner in Experiments 2 and 3. Our results showed that the JOL effects of font size are moderated or eliminated when inter-item relation is manipulated simultaneously with font size. Moreover, the smaller font led to better recall for related lists but not for unrelated lists across all three experiments. Therefore, our results demonstrate that individual cues may not be integrated with equal weight, and there can be a trade-off between item-specific and relational processing during the JOL process. Additionally, highlighting key information with larger fonts may not be optimal with related items.