2018 Friday Session C 0900

Friday, November 2, 2018 | Session C, Terrace Lounge | 9am

Knowing when to presuppose
A. Aravind, D. Fox, M. Hackl

Introduction: The use of presuppositional sentences demands a conversational common ground in which the presuppositions are already taken for granted (Stalnaker 1974 et seq.). Though this pragmatic requirement sets the foundations for the distinction between presuppositions and assertions—which must not be common ground information—little is known about its development.

We investigate children’s sensitivity to this requirement in a novel task, which probes biases about the knowledge state of the listener given the utterance of a presuppositional sentence.

Paradigm (Fig-1): Children listened to stories about an animal character and his two best-friends. The friends sometimes hide behind objects in the scene when they visit, making it difficult for the story-teller to identify them. The child is asked to say which friend is there based on what the main character says to the visitor. The two friends differ in their knowledge of some proposition p: the more “knowledgeable” friend knows that p is true, whereas the other is ignorant about the status of p. In the critical condition, the animal makes a statement presupposing p. If children are sensitive to the requirement that presupposed information must already be shared knowledge, they should say the knowledgeable friend. In the control condition, the character asserts, rather than presuppose, p. If children know that assertions contribute new information, they will be biased against the knowledgeable friend, who already knows that p is true.

Experiment-1, Too: Exp1 used presuppositional sentences with too. The speaker of a sentence like “I ate an apple, too” would be taken to assert that they ate an apple and presuppose that they ate something else. Example critical and control items are in (1). Results from 34 children (4;0-6;9) and 30 adults are in Figure-2. Both populations show a robust bias towards the knowledgeable listener in the critical condition and against the knowledgeable listener in the control condition.

These findings indicate that a key piece of pragmatic knowledge about presupposition-use is in place by age 4. Children’s pragmatic sophistication with presuppositions moreover shows this domain to be markedly different in development from other pragmatic phenomena, e.g. scalar implicatures.

Experiment-2, The: Unlike too, presuppositional sentences with definite descriptions (which presuppose the existence of a unique referent) can sometimes be used informatively. So the sentence “The car that I rented broke down” can be spoken to an audience who didn’t already know there was a unique rented car. This is because the descriptive content is rich enough to signal what is being presupposed, and cooperative listeners “accommodate” the speaker by tacitly adding that information to the common ground. The existence of such “informative” uses blurs the line between assertion and presupposition, complicating the child’s learning task. In Exp2, we ask how the availability of informative uses affects children’s expectations about the conditions governing presuppositional sentences with the. Results from 36 children (4;0-6;7) and 30 adults reveal near identical patterns to Exp1 (Figure-3). Thus, despite their divergent properties, children treat these presuppositions as a class uniformly governed by the same underlying pragmatic principles.