In this paper we describe an experiment designed to investigate the importance of eye gaze in humanoid avatars representing people engaged in conversation. We compare responses to dyadic conversations in four mediated conditions: video, audio-only, and two avatar conditions. The avatar conditions differed only in their treatment of eye gaze. In the random-gaze condition the avatar's head and eye animations were unrelated to conversational flow. In the informed-gaze condition, they were related to turn-taking during the conversation. The head animations were tracked and the eye animations were inferred from the audio stream. Our comparative analysis of 100 post-experiment questionnaires showed that the random-gaze avatar did not improve on audio-only communication. The informed-gaze avatar significantly outperformed the random-gaze model and also outperformed audio-only on several response measures. We conclude that an avatar whose gaze behaviour is related to the conversation pro...