Aizuchi as a sign of internal information processing and its interpretations by listeners

A back-channel is a short utterance made by nonprimary speakers. In the Japanese language back-channel is called "Aizuchi." Aizuchi has long been considered as a positive reaction to the primary speaker showing agreement or appraisal and or giving the right to continue speaking. Togashi argues that, in contrast to the conventional view, the essence of aizuchi is a sign of internal information processing in the mind of the one who uses aizuchi. The present study examined the usage of aizuchi as a non-primary speaker's internal information processing using Japanese map task dialogue. The result of our analysis showed that aizuchi often occurred when the primary speakers introduced an object known by the non-primary speakers into the conversation as predicted by Togashi's view of aizuchi. It was also suggested that the presence/absence of aizuchi was not necessarily a clear sign indicating the non-primary speakers have knowledge about the target object but rough but useful information to predict the knowledge state of the non-primary speakers.