For people to contribute to discourse, they must do more than utter the right sentence at the right time. The basic requirement is that they add to their common ground in an orderly way. To do this, we argue, they try to establish for each utterance the mutual belief that the addressees have understood what the speaker meant well enough for current purposes. This is accomplished by the collective actions of the current contributor and his or her partners, and these (...) result in units of conversation called contributions. We present a model of contributions and show how it accounts for a variety of features of everyday conversations. (shrink)

The results of two experiments, in which participants solved constructive tasks of the puzzle type, are reported. The tasks were solved by two partners who shared the same visual environment hut whose knowledge of the situation and ability to change it to reach a solution were different. One of the partners — the "expert" — knew the solution in detail but had no means of acting on this information. The second partner — the "novice " — could act to achieve (...) the goal, but knew very little about the solution. The partners were free to communicate verbally. In one third of the trials of the first experiment, in addition to verbal communication, the eye fixations of the expert were projected onto the working space of the novice. In another condition the expert could use a mouse to show the novice relevant parts of the task configuration. Both methods of facilitating the 'joint attention' state of the partners improved their performance. The nature of the dialogues as well as the parameters of the eye movements changed. In the second experiment the direction of the gaze-position data transfer was reversed, from the novice to the expert. This also led to a significant increase in the efficiency of the distributed problem solving. (shrink)

In this paper we report on an investigation into the principles underlying the choice of a particular referential expression to refer to an object located in a domain to which both participants in the dialogue have visual as well as physical access. Our approach is based on the assumption that participants try to use as little effort as possible when referring to objects. This assumption is operational-ized in two factors, namely the focus of attention and a particular choice of features (...) to be included in a referential expression. We claim that both factors help in reducing the effort needed to, on the one hand, refer to an object and, on the other hand, to identify it. As a result of the focus of attention the number of potential target objects is reduced. The choice of a specific type of feature determines the number of objects that have to be identified in order to be able to understand the referential expression. An empirical study was conducted in which pairs of participants cooperatively carried out a simple block-building task, and the results provided empirical evidence that supported the aforementioned claims. Especially the focus of attention turned out to play an important role in reducing the total effort. Additionally, focus acted as a strong coherence-establishing device in the studied domain. (shrink)

Herbert Clark argues that language use is more than the sum of a speaker speaking and a listener listening. It is the joint action that emerges when speakers and listeners, writers and readers perform their individual actions in coordination, as ensembles. In contrast to work within the cognitive sciences, which has seen language use as an individual process, and to work within the social sciences, which has seen it as a social process, the author argues strongly that language use embodies (...) both individual and social processes. (shrink)

Dialogue has its origins in joint activities, which it serves to coordinate. Joint activities, in turn, usually emerge in hierarchically nested projects and subprojects. We propose that participants use dialogue to coordinate two kinds of transitions in these joint projects: vertical transitions, or entering and exiting joint projects; and horizontal transitions, or continuing within joint projects. The participants help signal these transitions with project markers, words such as uh-huh, m-hm, yeah, okay, or all right. These words have been studied mainly (...) as signals of listener feedback (back-channel signals) or turn-taking devices (acknowledgment tokens). We present evidence from several types of well-defined tasks that they are also part of a system of contrasts specialized for navigating joint projects. Uh-huh, m-hm and yeah are used for horizontal transitions, and okay and all right for vertical transitions. (shrink)