Why no child or adult must learn de Morgan's laws
Abstract
Much recent research on child language has been inspired by linguistic principles uncovered by linguists working in the generative framework. Developmental psycholinguists have demonstrated young children’s mastery of a variety of linguistic principles; mostly syntactic principles, but also some semantic principles. The present paper contributes to research on the acquisition of semantics by presenting the findings of a new experiment designed to investigate young children’s knowledge of downward entailment, which is a basic semantic property of Universal Grammar. Section 2 describes how downward entailing operators work in natural languages. Section 3 addresses the issue of how a child could master the complex behavior displayed by downward entailing operators across natural languages. That section also reviews the findings of previous research on children’s knowledge of downward entailment. Section 4 presents the new experiment which was designed to investigate whether children’s knowledge of downward entailment extends to one of its logical properties, as illustrated by one of De Morgan’s laws. Section 5 offers some brief remarks on future research.