Role of inner speech in processing dialogues with mental and objective references

Theory of mind is a social cognition related to others' mental processes. Efficient use of this skill relies on two components; cognitive for inferring mental states from social scenarios and emotional for the recognition of others' emotions. Developmentally, theory of mind skills are correlated with language acquisition in children. Some of the hypotheses aiming to explain this correlation suggest that mental representations of others are acquired via internalized dialogues. These hypotheses that are inspired by Vygotsky's theory of language acquisition explain the relationship between language and theory of mind through "inner speech". The purpose of this study is (1) assessing theory of mind skills in adults in both emotional and cognitive dimensions and the relations between the two and both skills' relations with autistic tratis, (2) investigating the role of inner speech in mental processing of dialogues, (3) evaluating the relationship of inner speech's role in dialog processing and autistic traits. For this purpose, 375 neurotypical adults were examined for autistic traits and theory of mind skills. Theory of mind skills were assessed with Reading the Mind in the Eyes Test (RMET) and Humor Comprehension and Appreciation Test (hCAT) and autistic traits were measured with the Autistic Spectrum Quotient (AQ). Positive correlation was found between RMET and hCAT scores. AQ was found to be negatively correlated with non-mentalizing subscale of hCAT: Two seperate experiments were conducted to investigate the role of inner speech in dialogue comprehension. Two types of dialogues were written for the experiment. First type of dialogues included objective references and the second included mental references in utterances and each category included congruent and incongruent dialogues. The task in the first experiment required mentalization while the second was a word recognition (non-mentalizing) task. The experiments were repeated within 7-10 days and in one of the sessions subjects carried the task under articulatory suppression (AS). In both of the experiments, AS impaired accuracy scores regardless of category. However in the mentalizing task, AS impaired the reaction times of congruent dialogues more than the incongruent dialogues. Theory of mind scores of the participants was not significant in the effect of AS on both tasks. However AQ scores was a significant covariant in accuracy scores of the mentalizing task: AS had more detoriorating effect on incongruent dialogues in participants with higher autistic scores. This covariance effect and group difference was not found for the word recognition task. As a result, the role of inner speech on the mentalizing task of dialogues was found to be related with autistic traits and a similar effect for the non-mentalizing task was not observed.