A psychological experiment was conducted to capture the nature of Human-Human and Human-Agent Interactions where humans and computer agents coexist. Two factors were manipulated to investigate the influences of the `schema' about the opponent and the `actual opponent's conversation' on the characteristics of communication. The first factor, expectation about the opponent, was controlled by the experimenter's instruction, manipulating with which opponent (human or computer agent participants believed to be communicating. The second factor, the actual opponent, was controlled by manipulating with which opponent (human or computer agent) participants actually communicated. The results of the experiment suggest that the degree of the refinement of the conversation controlled as the actual opponent factor affected both emotional and cognitive characteristics of communication; however the schema about the opponent only affected emotional characteristics of communication. A detailed analysis based on the variance degree of conversation suggests that the actual opponent factor becomes dominant in the large contradiction group, whereas the schema factor appears only in the small contradiction group.