A main robot apparatus generates a sound scale command at a command
generating state (ST2) to enter into a state of waiting for a reaction of
a slave robot apparatus (ST3). When the slave robot apparatus outputs a
emotion expressing sound responsive to a sound scale command issued by
the main robot apparatus, the main robot apparatus recognizes this
emotion expressing sound to output the same emotion expressing sound. In
a state of the reaction action (ST4), the main robot apparatus selects an
action (NumResponse), depending on the value of the variable NumResponse
which has counted the number of times of the reactions to output the
action.
