Abstract
In the virtual environment, the virtual agent that has the general motivations is enough to live without interacting with the others. The virtual agent wants to interact with the others and it needs the social motivation as the foundation of its action. This thesis applies social motivations to the desire generation process of virtual agents. In the process, the mental state of virtual agent can respond to the event. According to social motivation, the virtual agent can generate the social constraints and desires to interact with the virtual environment.