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 own, or a shared perspective. In order to investigate the mental processes that underlie such perspective taking, we tracked people's eye movements while 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 addressees considered objects as potential referents even when the speaker could not see those objects, requiring addressees to use mutual knowledge to correct their interpretation. Thus, people occasionally use an egocentric heuristic when they comprehend. We argue that this egocentric heuristic is successful in reducing ambiguity, though it could lead to a systematic error.

When do speakers take into account common ground?

What role does common ground play in the production of utterances? We outline and test two models. One model assumes that common ground is involved in initial utterance planning, while the other model assumes that it only plays a role in monitoring. To compare these models, we focus on common ground as evidenced in physical co-presence. We had speakers describe objects for listeners in a modified version of the referential communication task. While descriptions under no time constraints appeared to incorporate common ground with the listener, common ground was not used when the speakers were under time pressure. These results suggest that speakers do not engage in audience design in the initial planning of utterances; instead, they monitor those plans for violations of common ground.

The illusory transparency of intention: linguistic perspective taking in text.

Subjects read scenarios where a speaker made a comment that, depending on information that was privileged to the subjects, could have been interpreted as sarcastic or not sarcastic. Their task was to take the perspective of an uninformed addressee and determine whether he or she would perceive sarcasm. Overall, when subjects believed that the speaker was actually being sarcastic they were more likely to attribute the perception of sarcasm to the addressee--even when the message was conveyed in writing and could not have involved disambiguating cues such as intonation. Data from four different experiments suggest that readers do use information that is perspective-irrelevant and thus pose a problem for theories of language use that assume readers only use "relevant" information.

Functional theory of illusory conjunctions and neon colors.

Illusory conjunctions are the incorrect perceptual combination of briefly presented colors and shapes. In the neon colors illusion, achromatic figures take on the color of an overlaid grid of colored lines. Both illusions are explained by a theory that assumes (a) poor location information or poor spatial resolution for some aspects of visual information and (b) that the spatial location of features is constrained by perceptual organization. Computer simulations demonstrate that the mechanisms suggested by the theory are useful in veridical perception and they are sufficient to produce illusory conjunctions. The theory suggests mechanisms that economically encode visual information in a way that filters noise and fills in missing data. Issues related to neural implementation are discussed. Four experiments illustrate the theory. Illusory conjunctions are shown to be affected by objective stimulus organization, by subjective organization, and by the linguistic structure of ambiguous Hebrew words. Neon colors are constrained by linguistic structure in the same way as illusory conjunctions.