Byrne is a talking head system, developed with two goals in mind: to allow artists to create entertaining characters with strong personalities, expressed through speech and facial animation; and to allow cognitive scientists to implement and test theories of emotion and expression. Here, we emphasize the latter aim. We describe Byrne’s design, and discuss some ways in which it could be used in affect-related experiments. Byrne’s first domain is football commentary; that is, Byrne provides an emotionally expressive running commentary on a RoboCup simulation league football game. We will give examples from this domain throughout this paper.