Human expressive interactions are characterized by an ongoing unfolding of verbal and nonverbal cues. Such cues convey the interlocutor’s emotional state which is continuous and of variable intensity and clarity over time. In this paper, we examine the emotional content of body language cues describing a participant’s posture, relative position and approach/withdraw behaviors during improvised affective interactions, and show that they re ect changes in the participant’s activation and dominance levels. Furthermore, we describe a framework for tracking changes in emotional states during an interaction using a statistical mapping between the observed audiovisual cues and the underlying user state. Our approach shows promising results for tracking changes in activation and dominance.