Automatic imitation of vocal actions is unaffected by group membership

Converging evidence from behavioural, neuroimaging, and neurostimulation studies demonstrates that action observation engages corresponding action production mechanisms, a phenomenon termed covert or automatic imitation. Behaviourally, automatic imitation is measured using the stimulus response compatibility (SRC) task, in which participants produce vocal responses whilst perceiving compatible or incompatible speech distractors. Automatic imitation is measured as the difference in response times (RT) between incompatible and compatible trials. It is unclear if and how social group membership, such as the speaker's sex, affects automatic imitation. Two theoretical accounts make different predictions regarding effects of group membership: the first predicts that automatic imitation can be modulated by group membership, while the second predicts that automatic imitation likely remains unaffected. We tested these predictions for participant sex and distractor sex in an online vocal SRC task. Female and male participants completed an SRC task presenting female or male distractor stimuli. The results show that automatic imitation is not modulated by group membership as signalled by sex. Implications of these results regarding the nature of automatic imitation as a largely stimulus-driven process are considered.