Quantitative analysis of gazes between a speaker and listeners was conducted from the viewpoint of mutual activities in floor apportionment, with the assumption that mutual gaze plays an important role in coordinating speech interaction. We conducted correlation analyses of the speaker's and listener's gazes in a three-party conversation, comparing native language (L1) and second language (L2) interaction in two types (free-flowing and goal-orient- ed). The analyses showed significant correlations between gazes from the current to the next speaker and those from the next to the current speaker during utterances preceding a speaker change in L1 conversation, suggesting that the participants were coordinating their speech turns with mutual gazes. In L2 conversation, however, such a correlation was found only in the goal-oriented type, suggesting that linguistic proficiency may affect the floor-apportionment function of mutual gazes, possibly because of the cognitive load of understanding/producing utterances.

The importance of conversation in second languages during international collaboration continues to increase, as does the risk of miscommunication caused by the differences in the linguistic proficiency of participants. This study provides a basis for monitoring each participant's status by studying the effects of linguistic proficiency on such communicative activities as utterances and gazes in second language conversations. In such conversations, we found that gaze produces different functions from those in native language conversations and that partners' linguistic proficiency may also affect gaze functions.

In our daily life, the interactive roles of leaders, followers, and coordinators tend to emerge from multiparty collaboration. The primary purpose of this study is to automatically predict the leading role in multiparty interaction by ubiquitous computing techniques. Even though the leading role has been predicted for an entire task, there has been little focus on evaluating how roles are reorganized during a task. To find the verbal and nonverbal cues that might predict roles, we asked neutral third parties to select the participant playing the leading role in an assembly task. We examined the correlation between behavioral data gathered during a task and third-party evaluations of the leading role player in terms of temporal alterations. The preliminary results suggest that task-oriented utterances and verification behaviors regarding progress status contribute to the prediction of the emerging and reorganized leader. Moreover, we discuss the implications of our findings for the design of applications that can enhance multiparty collaboration.