Taking perspective in conversation: The role of mutual knowledge in comprehension

When people interpret language, they can reduce the ambiguity of linguistic expressions by using information about perspective: the speaker's, their o wn, or a shared perspective. In order to investigate the mental processes t hat underlie such perspective taking, we tracked people's eye movements whi le they were following instructions to manipulate objects. The eye fixation data in two experiments demonstrate that people do not restrict the search for referents to mutually known objects. Eye movements indicated that addr essees considered objects as potential referents even when the speaker coul d not see those objects, requiring addressees to use mutual knowledge to co rrect their interpretation. Thus, people occasionally use an egocentric heu ristic when they comprehend. We argue that this egocentric heuristic is suc cessful in reducing ambiguity, though it could lead to a systematic error.