The contributions of mental state understanding and executive functioning to preschool-aged children's lie-telling

In this study, preschool-aged children's lie-telling behaviour was examined in relation to mental state understanding and executive functioning. Sixty-seven children aged between 25 and 43 months (M_{age in months}  = 34.80, SD = 4.39) participated in a temptation resistance paradigm (TRP). Children completed emerging ToM tasks measuring the following mental states: (1) diverse beliefs, (2) diverse desires, and (3) knowledge access. Children also completed measures of inhibitory control and working memory. In total, 63 of the 67 children peeked at the toy during the TRP, and a total of 26 of those children denied their transgression to the research assistant. Inhibitory control and understanding of knowledge access predicted lie-telling behaviour. Results are discussed in relation to a developmental model of children's lie-telling behaviour. Statement of contribution What is already known on this subject? The relationship between lie-telling, executive functioning, and ToM has been established in older children (aged 4 and above). Inhibitory control plays a role in young children's lie-telling (aged 2-4). Children above 3 years of age have some understanding of mental states. What does this study add? Very young children (2-3-year-olds) also possess an understanding of mental states. Mental state understanding is related to 2-3-year-old children's lie-telling behaviours and may be more predictive than inhibitory control. While the results were not significant, this study is the first to look at the unique role of working memory in very young children's lie-telling.