Abstract/Summary

Mirror systems are widely thought to map perceptual representations of others’ actions onto the observer’s corresponding motor representations. This includes ‘opaque’ actions, which are unobservable when performed by the self (e.g. facial expressions and attention shifts). To date, few studies have looked at mirror systems for these actions in the infant brain, and even fewer have investigated how such systems might develop. Therefore, the main aims of the research presented in this thesis were to investigate potential mirror systems for opaque actions in very young participants, and how early social experience may influence the development of these systems. This was done using electroencephalography (EEG) to measure mu desynchronization, an index of mirror system activity, while infants and young children observed and executed various actions, and the manual coding of early mother-infant interaction videos. Two of the included studies, Chapters 2 and 4, were designed to look at putative facial mirror system activity in 30-month-old children and 9-month-old infants, respectively. The Chapter 4 study also considered the influence maternal mirroring of infant facial expressions at 2 months postpartum may have on mu desynchronization during observation of expressions at 9 months. The third study (Chapter 5) was designed to investigate potential involvement of a mirror system in the processing of others’ attention shifts at 6.5 and 9.5 months of age. Infants in this study had been recorded interacting with their mothers at 3.5 and 6.5 months postpartum, and the relationship between attentionrelated behaviours during early social exchanges and mu desynchronization in the EEG experiments was examined. Altogether, findings from this research suggest that mirror systems are involved in the processing of facial expressions and attention shifts from a very young age, and that early social interactions provide infants with the experience crucial for development of such systems.