The lexical interface in L1 acquisition: What children have to say about radical concept nativism

In the ongoing philosophical debate over the origins and nature of lexical concepts stemming from the work of Fodor (1970, 1998, 2000, 2008), the potential of first language acquisition studies as a source of evidence has been somewhat overlooked. At the lexical interface with syntax, a restricted set of lexical conceptual elements can be shown to play a pivotal role in the generation of syntactic representations, and patterns of syntactic development can elucidate the nature of such elements. An experiment is described which reveals mature knowledge of interface principles in this domain in early syntactic production. It is argued that first language research of this type can provide much-needed observable evidence for lexical semantic decomposition and against radical concept nativism.