1. A robot comprising: a first analyzer for analyzing phrase and action of a human partner to detect a recognized behavior of the partner; a second analyzer for analyzing a state of a plurality of people listening to utterances from said partner and said robot to detect a recognized state of said people; a scenario memory for storing a scenario describing a dialogue between said partner and said robot; and a processor for making reference to a portion of said scenario in said memory according to the recognized behavior of said partner and the recognized state of said people, and determining a behavior of said robot according to the referenced portion of said scenario.