Understanding by addressees and overhearers

In conversation speakers design their utterances to be understood against the common ground they share with their addressees—their common experience, expertise, dialect, and culture. That ordinarily gives addressees an advantage over overhearers in understanding. Addressees have an additional advantage, we propose, because they can actively collaborate with speakers in reaching the mutual belief that they have understood what was said, whereas overhearers cannot. As evidence for the proposal, we looked at triples of people in which one person told another person in conversation how to arrange 12 complex figures while an overhearer tried to arrange them too. All three began as strangers with the same background information. As predicted, addressees were more accurate at arranging the figures than overhearers even when the overhearers heard every word. Other evidence suggests that the very process of understanding is different for addressees and overhearers.