Shifting Perspectives Between ‘Self’ and ‘Other’ in Healthy Adults: A Novel False-Belief Task with Behavioural and EEG Measures

This research explored how the Theory of Mind (ToM) mechanism functions in healthy adults, specifically looking at the differentiation between ‘Self’ and ‘Other’ in belief-attribution abilities, and how we switch between ‘Self’ and ‘Other’ perspectives. Adult participants completed a newly established computerized false-belief task in which they attributed beliefs to themselves and other people, in a matched design, to allow direct comparison of behavioural and neural correlates of belief attribution to the ‘Self’ and ‘Other’. Participants responded faster and more accurately to self-oriented than other-oriented questions, which was supported by electroencephalography (EEG) measures, largest across central parietal lobes from 550ms after stimulus onset. Critically, when a ‘perspective-shift’ was required in a trial, shifting from Self-to-Other was significantly slower and more error prone than shifting from Other-to-Self. In contrast, in ‘no perspective-shift’ trials, there was no difference between Self-to-Self and Other-to-Other trials. EEG measures revealed an early onset significant interaction between Perspective-Shifting and Perspective-Type (Self/Other), from 300 ms after stimulus onset, further supporting the key role of perspective-shifting in ToM processes. Results indicate that the ‘Self’ is consistently processed, whilst the ‘Other’ is only processed when explicitly necessary, and support the notion of a Self/Other differentiation within the ToM mechanism, at both a behavioural and neural level.