Automatic imitation is a nonverbal behaviour that is central to social cognition and influences social connectedness. Despite a recent interest in examining the factors that influence imitation behaviour, there is still much that is unknown. The following studies employ a range of methods to investigate how features of oneself and of an interaction partner impact on imitation behaviour. In the first empirical chapter (Chapter 2), a series of behavioural experiments elucidate the influence of facial signals from an interaction partner on subsequent imitation behaviour. Chapters 3 and 4 employ large sample behavioural approaches to investigate the relationship between automatic imitation and individual differences in one’s own stable personality characteristics. In Chapter 4 this approach is combined with a functional magnetic resonance imaging (fMRI) study. This chapter examines an unpredicted individual difference result from Chapter 3, and the brain regions involved in supporting this difference in the control of automatic imitation compared to a non-­‐social inhibitory control task. As a whole, the results from this thesis suggest that imitation is sensitive to facial cues from an interaction partner that signal information pertinent to a current social interaction, rather than cues about the interaction partner’s long-­‐term behaviour. Additionally, imitation is relatively resistant to individual differences in one’s own stable personality characteristics. This thesis has implications for social cognitive neuroscience research more broadly and advocates the use of large sample behavioural studies in combination with fMRI studies in order to increase reproducibility in the field and confidence in neuroimaging findings.