“…The screen-based 'talking-head' is a powerful device for mediating interaction between humans and machines, enabling a form of interaction that mimics direct communication between humans [2,5,8,[16][17][18][19]22]. The experience of realism is further enhanced when the computer is equipped with visual and auditory senses with which to perceive the user [1,3,6,9,10,12,20,21,23,[26][27][28].…”