The paper presents an evaluation method to assess impressions toward a computer-generated creature through human-computer interaction. The aim of our study is to construct a mechanism on a computer to realize empathic interaction between humans and creatures. In this paper, we examine the effect on personality cognition of a virtual creature when the creature replies with different timing to a human utterances. The creature has an abstract appearance and a non-linguistic voice. We control the following three conditions for timing of the creature's response: a) alternation, b) overlap, and c) neutral condition. As a result, we found that the evaluation value of the alternation condition shows more positive behavior than that of the overlap and neutral conditions when the creature has the above features.