Yes / 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. / Japanese Society for the Promotion of Science: KAKENHI Grant No. 16K04327.

This thesis focuses on the relationship between theory of mind and language skills in Czech preschoolers. The theoretical part summarizes current knowledge about theory of mind, its relationship to language skills, and some areas of development of preschool children. The empirical part describes the research of the relationship between theory of mind and language skills of Czech preschoolers. Fifty-five children in total participated in this research, twenty children in a younger group (m=42 months), and thirty-five children in an older group (m=54 months). Theory of mind has been assessed by two false-belief tasks: Sally-Ann Task, and Smarties task. Language skills were tested by Grammar reasoning test, and Understanding of grammar test from test battery of Seidlová-Málková and Smolík (2014). The older group has significantly better results in false-belief tasks then the younger group. Despite anticipated results, there was not statistically significant difference between the younger and the older groups' language skills. A moderate positive correlation was found between language skills and false-belief understanding in both groups. KEYWORDS Theory of Mind, False Belief Understanding, Language Skills, Preschoolers, Sally-Ann Task, Smarties Task