Abstract
This paper is concerned with two aspects of metacognitive knowledge: its developmental trend of "from overconfident to normal" and its elaboration mechanism of "metacognitive monitoring of reflecting on knowledge." Two experiments were carried out to explore the two metacognitive aspects of word knowledge, the results indicating that (1) junior high school learners of English who have high proficiency turned out to be significantly more confident in their word knowledge than high school and college ones, and (2) the metacognitive monitoring of reflecting on knowledge was found to be of psychological reality concerning learners' confidence, as a part of metacognitive knowledge, in word knowledge. These results will be discussed in terms of several issues associated with language learning.
