Children’s Semantic Representations of a Science Term

School-age children acquire hundreds of new words each year, many of which are acquired incidentally, from uses in discourse contexts. Although children are adept word learners, lexical acquisition from oral language is not necessarily inevitable. Children have particular difficulties in the acquisition of terms that involve complex semantic representations, such as science terms (Braisby, Dockrell, & Best, 1999). Learning science terms poses particular challenges for acquisition because they are ‘conceptually complex’ and can be understood at various levels of abstraction (Meyerson et al, 1991). Our study investigated the kinds of knowledge children acquire about a science term during the process of lexical acquisition. Understanding the process of lexical acquisition requires a thorough assessment of the nature of children’s wordrelated knowledge (Beck & McKeown, 1991). While previous studies of word learning have focused on what drives children’s acquisition of word meanings, less is known about the nature of children’s lexical representations, particularly those relating to complex vocabulary. When children acquire a new word, they must identify the sound in the speech stream to encode a phonological representation and then establish a mapping between the word and concept. Ultimately a detailed semantic representation is developed for the new term. Because of this multifaceted representation, ascertaining the nature of vocabulary knowledge requires multiple measures (Beck & McKeown, 1991). These measures should include both production and comprehension, moving beyond the conventional multiple-choice comprehension task. Indeed, recent research has indicated that tapping into children’s knowledge of conceptually difficult concepts may necessitate creative methods, such as drawing-based assessments (Gross & Teubal, 2001). Assessing knowledge across a range of tasks does not, on its own, provide information about the maturity of children’s lexical representations. Although seldom used in lexical acquisition research, comparison with adults’ performance allows us to identify knowledge gaps.