Audience size influences actors' anxiety and associated postures on stage.

Public performance is a reported source of anxiety. While the relationship between emotion and postural laterality is well-known in animals, few studies have tested the possible link between audience effect, anxiety and head orientation in humans. The Valence-Specific Hypothesis posits that the left/right sides of the brain are specialized for processing positive/negative emotions respectively. Here, actors performed a piece in the presence of small, medium and large audiences. They self-reported feeling more anxious when the audience was large (also confirmed with speech analyses), but the small audience was scored with the lowest preference. We also found that the large audience was associated with the fewest orientations facing the public. Moreover, both large and small audiences were associated with more left-side than right side orientations. Here, actors' emotions influenced lateralized positioning, with a tendency to use the left visual field (i.e. right hemisphere) in more anxious and less preferred situations, supporting the Valence-Specific hypothesis.