• Dissociating neural signatures of mental state retrodiction and classification based on facial expressions

      Kang, K.; Schneider, D.; Schweinberger, S.R.; Mitchell, Peter (2018-08-22)
      Posed facial expressions of actors have often been used as stimuli to induce mental state inferences, in order to investigate 'Theory of Mind' processes. However, such stimuli make it difficult to determine whether perceivers are using a basic or more elaborated mentalizing strategy. The current study used as stimuli covert recordings of target individuals who viewed various emotional expressions, which caused them to spontaneously mimic these expressions. Perceivers subsequently judged these subtle emotional expressions of the targets: in one condition ('classification') participants were instructed to classify the target's expression (i.e. match it to a sample) and in another condition ('retrodicting') participants were instructed to retrodict (i.e. infer which emotional expression the target was viewing). When instructed to classify, participants showed more prevalent activations in event-related brain potentials (ERPs) at earlier and mid-latency ERP components N170, P200 and P300-600. By contrast, when instructed to retrodict participants showed enhanced late frontal and fronto-temporal ERPs (N800-1000), with more sustained activity over the right than the left hemisphere. These findings reveal different cortical processes involved when retrodicting about a facial expression compared to merely classifying it, despite comparable performance on the behavioral task.
    • Modelling the executive components involved in processing false belief and mechanical/intentional sequences

      Tsuji, H.; Mitchell, Peter (2019-06)
      To understand the executive demands of the false-belief (FB) task relative to an alternative theory-of-mind (or mechanical causality) task, picture sequencing, the present study used path analyses. One hundred and sixty-six children between 3 and 6 years old completed the FB and picture-sequencing tasks, three executive function tasks (updating, inhibition, and shifting), and the receptive language test. The model with the best fit indicated that FB performance had a direct contribution from shifting of attention and inhibitory control, which was independent of the significant contribution made by picture sequencing. This model indicates that FB inference requires more executive processing than picture sequencing, which is used as an alternative task to measure theory of mind. Statement of contribution What is already known on this subject? The majority of researchers use the false-belief task to assess mentalizing ability in young children. Sources of information used in various different mentalizing tasks require different levels of cognitive demand. Many executive functions (EFs) are involved in children's judgements of false belief. What does this study add? A statistical model was created to compare processing requirements of false-belief and picture-sequencing tasks. The model supported the claim that the false-belief task involves considerably more than just mentalizing. Shifting the focus of attention was an EF that was found to be a key component of performance in the false-belief task.