Motivation: We are interested in social interaction as a natural means for human-machine interaction, as a facilitator for learning more complex behavior, and as a well-studied instance of developmental progression . Robust gaze control is important for social interaction – finding and fixating faces, maintaining eye contact, following gestures, tracking objects, etc. Cog currently has saccadic and smooth pursuit eye movements, which direct gaze laterally across the visual field. Vergence fixates gaze on objects at different depths in the visual field. This ability will improve pre-existing behaviors implemented on Cog and facilitate new behaviors that rely on depth perception.