Pragmatic theories generally agree that the derivation of implicit meaning depends on the assumption that the speaker is cooperative and knowledgeable, as well as the contextual relevance of the implicature. Studies on scalar implicature priming have investigated the latter, but the influence of the first two factors remains understudied. Here, we investigated the effect of the presence (or absence) of a cooperative and knowledgeable interlocutor on the derivation of both lexical and ad-hoc scalar implicatures. We found an effect of implicature priming within and across different scales. The presence of an interlocutor increased implicature derivation overall and partially enabled priming effects across lexical and ad-hoc scales. These results provide some support for the existence of a scalar implicature derivation mechanism shared by lexical and ad-hoc scales, and they highlight the importance of the speaker’s cooperative attitude and knowledgeability as part of this process. Moreover, they show the importance of psycholinguistic investigations to be carried out using rich conversational contexts that include intentional agents.
