Abstract

It’s not enough to tell the truth, if it is not the whole truth. But how do young children come to master this conversational principle? One way of looking into this question is by studying whether children reject other people’s utterances that contain only some of the information that they could have communicated. Another way of looking into this question is by studying whether children themselves give all the information that they should give. These two paradigms address the twin aspects of the same pragmatic skill, informativeness, that is, the ability to estimate how much information should be communicated in a situation, from a comprehender’s and a speaker’s perspective respectively. To the best of our knowledge, the two aspects of informativeness have not been investigated in combination, and their developmental trajectory is not established. We present a number of studies that look into both aspects of informativeness within the same population of 5-, 7-, 9-, and 11-year old typically-developing English-speaking children, as well as an adult control group. In this presentation we will pay particular attention to cases where partial information is given (a) in circumstances of knowledge of the outcome, in which case partial information is indeed under-informative, and (b) in circumstances of uncertainty and ignorance (as when one makes a bet or a guess when they do not know the outcome of a story). We will see that participants do take the knowledge state of the interlocutor into account when judging if an utterance is under-informative or not. We will explore the implications of this research for investigations into populations with a language and/or a theory-of-mind deficit.