In the present study, primary school children's ability to give accurate confidence judgments (CJ) was addressed, with a special focus on uncertainty monitoring. In order to investigate the effects of memory retrieval processes on monitoring judgments, item difficulty in a vocabulary learning task (Japanese symbols) was manipulated. Moreover, as a first exploratory step to uncover fast and retrieval bound (implicit) monitoring processes that take place before explicit CJ are openly reported, fixation time allocation during recognition and monitoring was recorded with an eye-tracking device. Results revealed developmental progression in uncertainty (but not in certainty) monitoring between the age of 7 and 9 years. Differences in CJ across levels of item difficulty point to a substantial impact of retrieval processes on 9-yr-olds' but not on 7-yr-olds' monitoring. Eye-tracking data revealed an overall bias towards medium and high CJ, and confirmed evidence on developmental progression in monitoring skills. (Contains 1 footnote, 2 tables, and 3 figures.)