The Role of Partitivity in Child Language

In this squib, we investigate the nature of the phenomenon of isomorphism, which expresses the observation that young children, unlike adults, display a strong preference for the interpretation of sentences containing negation and quantified noun phrase (NPs) that corresponds to the surface syntactic position of these scopetaking operators (Gualmini (2003), Lidz and Musolino (2002), Musolino (1998), Musolino, Crain, and Thornton (2000)). Here we focus on sentences containing negation and indefinite objects, as in The Smurf didn’t catch two birds or The detective didn’t find some guys. Based on the intuition that indefinites can give rise to what has been called either a “presuppositional/quantificational” or a “cardinal” interpretation (Diesing (1992), drawing on Milsark (1977)), we propose that isomorphism, as it pertains to indefinite objects, arises when children fail to select the so-called presuppositional interpretation of the NP and its associated logical representation.1 This account predicts that when plain NPs like some Ns and two Ns are replaced by inherently presuppositional ones, such as partitives (e.g., two of the Ns and some of the Ns), children should be more likely to access the nonisomorphic, wide-scope interpretation of the indefinite objects with respect to negation. This prediction is tested and verified in two experiments designed to assess young children’s interpretation of sentences containing negation and partitive NPs in object position. LANGUAGE ACQUISITION, 12(1), 97–107 Copyright © 2004, Lawrence Erlbaum Associates, Inc.