This paper reports on the development of a multi-agent simulation of small group discussion that focusses on the interaction and the coordination of turn-taking. We describe the addition of nonverbal behaviours, such as gaze, gestures, posture shifts and head and facial expression, to the model; how the agents in the simulation take these behaviours into account in their decisions to speak, to stop, or to give feedback. The simulation is to be evaluated comparing its statistical profile against the statistics generated by a simpler, base model, one without the nonverbal behaviours, to show that it better approximates the statistics of a real group discussion. The properties to be assessed include mean transition intervals, turn lengths, relation of gaze to speaking order, frequency of simultaneous starts, and of feedback.
