In this study, first the level of interconnectedness of the key concepts concerning the topic of physical and chemical changes in pre-service chemistry teachers' (PSCTs') semantic memories was explored. Second, the group cognitive structures of the PSCTs that contain associations between these key concepts and the response concepts that appeared…

Children improve at word learning during the 2nd year of life--sometimes dramatically. This fact has suggested a change in mechanism, from associative learning to a more referential form of learning. This article presents an associative exemplar-based model that accounts for the improvement without a change in mechanism. It provides a unified…