Avatars seem to be getting ever more lifelike, with more realistic visual appearance, speech, and body motion.

But as an avatar approaches reality, it could fall into the “Zombie Zone,” in which expectations that a character is actually human are suddently “violated by something that slightly wrong in the voice, or the face, or in the way it moves, and it gives you a horrible feeling that is not real,” said Ruth Aylett, professor of intelligent virtual environments at the University of Salford.