Digital immersive virtual environment technology has enormous implications for human-computer interaction. Many qualities of digital human representations, particularly those of human-appearing agents, are important for social engagement and social influence. In particular, non-verbal behaviors play a critical role. Among such behaviors, arguably the most important are facial expressions of emotion, which are critical for meaningful renderings of digital agents. To date, computational models that would permit such renderings are less than optimal. This project will employ a cyclical two-step process to develop a computational model that embeds dynamic expression and socially engaging non-verbal gestures into talking avatars, and experimentally tests its usability within digital virtual environments involving human-digital agent interaction.