Recent work on metacognition indicates that monitoring is sometimes based itself on the feedback from control operations. Evidence for this pattern has not only been shown in adults but also in elementary schoolchildren. To explore whether this finding can be generalized to a wide range of age groups, 160 participants from first to eighth grade participated in a study based on a self-paced study time (ST) allocation paradigm. In contrast to previous studies, picture pairs instead of word pairs were used as stimuli to compensate for reduced reading skills in younger participants. Actual ST and judgments of learning (JOLs) made at the end of each study trial were used as core variables. The results are in line with previous findings, in that children's JOLs decreased with increasing ST, suggesting that JOLs were based on the memorizing effort heuristic that easily learned items are more likely to be remembered. Weaker inverse relationship between JOLs and ST was found for the younger children. Overall, these results underline the importance of mnemonic cues in shaping metacognitive feelings not only in adults but also in older children and expose a developmental trend in their use along childhood.