Discovering how people judge their memories has been a major issue for metacognitive research for over 4 decades; many factors have been discovered that affect people’s judgments, but exactly how those effects are mediated is poorly understood. For instance, the effect of word pair relatedness on judgments of learning (JOLs) has been repeatedly demonstrated, yet the underlying basis of this substantial effect is currently unknown. Thus, in three experiments, we assessed the contribution of beliefs and processing fluency. In Experiment 1, participants studied related and unrelated word pairs and made either prestudy JOLs or immediate JOLs. Participants gave higher estimates for related than for unrelated pairs, suggesting that participants’ beliefs at least partially drive the relatedness effect on JOLs. Next, we evaluated the contribution of processing fluency to the relatedness effect either (1) by disrupting fluency by presenting half the pairs in an aLtErNaTiNg format (Experiment 2) or (2) by measuring how fluently participants processed pairs at study and statistically estimating the degree to which conceptual fluency mediated the effects of relatedness on JOLs (Experiment 3). Results from both experiments indicated that fluency contributes minimally to the relatedness effect. Taken together, these results indicate that people’s beliefs about how relatedness influences memory are responsible for mediating the relationship between relatedness and JOLs. In general, empirically establishing what mediates the effects of other factors on people’s judgments remains a major agenda for advancing theory of metacognitive monitoring.
