We investigate the relationship between backchannels and the syntactic structure in the delimited preceding utterances in attentive listening such as counseling. First, we find out the relationship between particular patterns of backchannels and the category of the clause boundary. Next, we analyze the syntactic structure by using the depth of the syntax tree and the number of cases related to the end of utterance. It is shown that there is a relationship between particular patterns of backchannels and the complexity of the preceding utterances. The results suggest that we can choose different kinds of backchannels depending on the preceding utterance.
