語彙習得理論は何を説明しなければならないのか：30年の軌跡を振り返って

抄録

This paper traces the development of theories of lexical acquisition in the past three decades to discusses what needs to be explained in them. In the last two decades of the 20^th century, the so-called constraints-based nativist theories raised and flourished. While it explained certain phenomena, the scope of these theories was limited, and have not addressed the most critical questions for lexical development. In this paper, I argue that theories of lexical development must explain not only how infants begin the endeavor of lexical learning but also how they proceed from there to possess the adult lexicon, which is extremely vast, complex, and largely language-specific system of abstract symbols. For this purpose, following issues should be addressed in theories of lexical acquisition: (1) how symbols can be grounded to the body, as proposed by Steven Harnad (1990); (2) what cognitive abilities or dispositions enable Symbol Grounding, and whether (or in what degree) they are human-specific or evolutionary shared with our ancestors; (3) the mechanism with which human children bootstrap themselves from the initial, rudimentary symbols to adult lexical representation; (4) what cognitive abilities enable such bootstrapping processes.