Beliefs About the Speaker's Reasoning Ability Influence Pragmatic Interpretation: Children and Adults as Speakers.

The cooperative principle states that communicators expect each other to be cooperative and adhere to rational conversational principles. Do listeners keep track of the reasoning sophistication of the speaker and incorporate it into the inferences they derive? In two experiments, we asked participants to interpret ambiguous messages in the reference game paradigm, which they were told were sent either by another adult or by a 4-year-old child. We found an effect of speaker identity: if sent by an adult, an ambiguous message was much more likely to be interpreted as an implicature, while if sent by a child, it was a lot more likely to be interpreted literally. We also observed substantial individual variability, which points to different beliefs and strategies among our participants. We discuss how these speaker effects can be modeled in the Rational Speech Act framework.