When pragmatics matters more for truth-value judgments: An investigation of quantifier scope ambiguity

Abstract

Investigations of linguistic meaning rely crucially on truth-value judgments, which assess whether a sentence can truthfully describe a given scenario. In investigations of language acquisition, truth-value judgments are used to assess both the target knowledge adults have and the developing knowledge children have at different ages. On the basis of truth-value judgments, researchers have concluded that differences between how children resolve ambiguous utterances and how adults do so persist until at least age five. Current explanations compatible with the experimental data attribute these differences to both grammatical processing and pragmatic factors. Here, we use computational cognitive modeling to formally articulate one hypothesis about the ambiguity-resolution process that underlies child and adult judgments in a truth-value judgment task; crucially, the model can separate out the individual contributions of specific grammatical processing and pragmatic factors to the resulting judgment behavior. We find that pragmatic factors play a larger role than grammatical processing factors in explaining children’s non-adult-like ambiguity resolution behavior. Interestingly, the model predicts qualitative similarity between child and adult ambiguity resolution. Given this prediction, we then extend our model to show how the same processes may be active in adult ambiguity resolution. This result supports continuity in the development of ambiguity resolution, where children do not qualitatively change how they resolve ambiguity in order to become adult-like. We discuss the implications of our results for acquisition more generally, including both theories of development and methods for assessing that development, as well as the generalizability of this model of ambiguity resolution beyond the specific cases we consider.