How do people construct mutual beliefs in task-oriented dialogues?

The present study investigates how mutual beliefs are achieved by examining the relationship between actual behaviors and utterances in task-oriented dialogues. According to a widely accepted model, mutual belief about a task is considered to be achieved when a listener accepted utterances about the task given by another agent and gives some signs of task completion to the agent. However, by analyzing Japanese Map Task Dialogue Corpus ( JMTDC), we found vast majority of conversations ( 94%) did not follow what was suggested by the model. We categorized those non-standard dialogues into six categories, namely, delayed acceptance, premature sign of completion, execution postponement, silent adjustment, unconfirmed, and indirection. We further analyzed those six categories carefully to see how and when participants were able to achieve mutual belief in the dialogues.