Abstract
The present study has investigated how mutual briefs about task executions are updated
during collaborative tasks using the Japanese map task corpus. The results have
shown that the current models describe only part of mutual brief updating processes,
and that there exist other types of processes. According to the current models, a mutual
belief is considered to be achieved when the instruction follower accepts instructions
given by the instruction giver and gives some sign of actually completing the given
task. However, the present study has shown that mutual beliefs could be achieved even
when the follower neither follows the instruction nor gives any sign of completion. The
analysis indicates that the conversations in map tasks do not necessarily require prior
planning and conversations to obtain clear mutual briefs about the goals to achieve the
way the current models expect. Rather, ambiguous mutual beliefs and somewhat independent
actions, coupled with inference about mutual goals, are sufficient to achieve
the map tasks. In order to explain these results, we have proposed more detailed
mechanisms about how mutual beliefs update.
