Displays as formalized intention movements. Displays are elaborations upon two types of movements, social instrumental habits and protective reflexes. Fridlund makes a passing comment which is important. The Nerves and Muscles of the Face. Greater spatial extensibility incorporates greater contralateral neural connections.
Separate nerves control each group.
Facial Reflexes and the Ontogeny of Facial Displays. Fridlund didn't like Darwin's treatment of blushing. The State of the Evidence. Audience Effects and the Context Dependency of Displays. If displays serve social motives throughout phylogeny, then across species their occurrence should be a function not only of the proximal elicitors, but of those who are present, one's aims towards them, and the context of the interaction.