Investigations of scope ambiguity resolution suggest that childbehavior differs from adult behavior, with children strugglingto access inverse scope interpretations. For example, childrenoften fail to accept Every horse didn’t succeed to mean not allthe horses succeeded. Current accounts of children’s scope be-havior involve both pragmatic and processing factors. Inspiredby these accounts, we use the Rational Speech Act frameworkto articulate a formal model that yields a more precise, ex-planatory, and predictive description of the observed develop-mental behavior.