Social anxiety disrupts interpersonal coordination during conversation: an investigation of behaviour matching and collaborative co-action during social interactions

[Truncated abstact] The present dissertation identifies a specific social behaviour deficit in social anxiety that can help explain why socially anxious individuals elicit less positive reactions from those they interact with. Six studies assessed indices of interpersonal coordination between anxious participants and their conversation partners. The findings indicate that compared with non-anxious others, socially anxious individuals' capacity for aligning their behaviour to match their partner’s behaviour may be relatively intact, but they engage less in behaviour that is synchronised in time and complements or 'comes together' with a partner's coinciding behaviour to form co-action. Studies 1 - 3 found no evidence of a social anxiety linked deficit in interpersonal alignment, as indexed by similarity between conversation partners in their ways of speaking. Participants engaged in picture description tasks with a confederate and no differences were noted between socially anxious and non-anxious participants in the extent to which they re-used the confederate's choice of syntax (Study 1) or words (Study 2), nor in the rate at which they aligned with the confederate on ways of referring to items (Study 3). Study 4 found that socially anxious participants engaged less than others in collaborative, complementary joint action with a partner. During unscripted conversations with peers, socially anxious participants contributed fewer collaborative listener responses, especially those responses like making gestures, facial expressions or exclamations that helped to illustrate what their partner was saying. Study 5 replicated this less collaborative listening behaviour in non-anxious participants via a partial distraction task and noted that it corresponded with poorer interpersonal ratings from conversation partners.