It is important to identify how much the appearance of a humanoid robot affects human behaviors toward it. We compared participants' impressions of and behaviors toward two real humanoid robots in simple human-robot interaction. These two robots have different appearances but are controlled to perform the same recorded utterances and motions, which are adjusted by using a motion capturing system. We conducted an experiment where 48 human participants participated. In the experiment,

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... interacted with the two robots one by one and also with a human as a reference. As a result, we found that the different appearances did not affect the participants' verbal behaviors but did affect their non-verbal behaviors such as distance and delay of response. These differences are explained by two factors, impressions and attributions. Index Terms -human-robot interaction; robot appearance; body movement analysis; humanoid robots.