Topic-Shift Characteristics of Japanese Casual Conversations Between Elderlies and Between Youths

To support senior citizens’ smooth conversations, we have developed a conversation support system that provides several topics for speakers. To effectively support conversation, the system should select suitable topics and speaking styles for the speakers while observing topic-shift situations regarding their previous conversations. In this study, we discuss the differences in conversation styles and topic-shift characteristics between elderlies and those between youths. A comparison of conversations of elderly people and youths revealed two distinct characteristics. The casual conversations of elderlies tended to include long utterances with the speakers firmly expressing their knowledge or opinion. By contrast, the conversations of youths did not reveal long utterances and they tended not to express their opinions at once, but only gradually, after watching the reaction of the other person. Further, elderly speakers tended to talk on a topic more in-depth and did not get sidetracked compared with young speakers. Moreover, the boundary of topics in the case of elderly people tended to be clearer than in the case of youths. As a result of generation identification experiments using “the number of utterances by each topic,” “the number of content words in each utterance,” and “the deviation of word similarity,” the precision rate for youths is 90.5% but that for elderlies is 42.2%. This suggests that these parameters are effective to extracting the young speakers with certainty.