From self to social cognition : a new paradigm to study differentiations within the Theory of Mind mechanism and their relation to executive functioning

Theory of Mind (ToM) refers to the ability to attribute mental states to oneself and other people. In this thesis, I present a new paradigm, the Self/Other Differentiation task, which was designed to assess ToM abilities – specifically, the ability to attribute belief states to the ‘Self’ and ‘Other’ – in typically developed, healthy adults. By focussing on fully developed ToM abilities, we aimed to increase understanding of how the ToM mechanism is structured and functions in everyday life, and how individual ToM components may differentially relate to executive functioning (EF) abilities. The Self/Other Differentiation task is a computerized false-belief task utilizing a matched- design to allow direct comparison of self-oriented versus other-oriented belief- attribution processes. Using behavioural (response times/error rates) and electrophysiological (EEG) methods, the work presented in this thesis provides evidence of a clear and distinct differentiation in the processing of ‘Self’ versus ‘Other’ perspectives in healthy ToM. We established a key role of perspective-shifting in ToM, which we hypothesize plays a crucial role in day-to-day communications; shifting from the Self-to-Other perspective was significantly harder (longer and more error prone) than shifting from the Other-to-Self perspective, suggesting that the ‘Self’ forms the stem of understanding the ‘Other’. EEG analysis revealed these effects were present across fronto-lateral and occipital-lateral areas of the brain, particularly across the right hemisphere in parietal regions. We provide evidence of these features as universal, core components of the ToM mechanism, with data collected from both Chinese and Western cultures illustrating similar patterns of results. Results regarding the relationship between ToM and EF were mixed, with one study finding that affective EF positively correlates with ToM task performance, whilst non-affective EF does not, and a further two studies finding no such differential relationship. The Self/Other Differentiation task provides the opportunity to establish the features of ‘typical’ ToM processes in healthy adults, to further our understanding of how the mature ToM mechanism functions