Speakers' overestimation of their effectiveness.

Successful communication depends in part on an ability to anticipate miscommunication. We investigated speakers' ability to gauge their addressees' understanding. Participants in our experiments were asked to say ambiguous sentences while attempting to convey a specific intention to their addressee. When they estimated the addressee's understanding of the intended meaning, they showed a consistent tendency to overestimate their effectiveness. They expected the addressee to understand more often than the addressee actually did. In contrast, overhearers who were informed about the speakers intention did not systematically overestimate the speakers' effectiveness. Our findings suggest that when speakers monitor their own utterances, they do not act as unbiased observers. Instead, they underestimate the ambiguity of their own utterances and overestimate the extent to which their disambiguating cues make their intention transparent. Such overestimation could be a systematic source of miscommunication in natural conversation, and should be accounted for by any theory of language production.