In the present study, children's (2-to 5-years old) lie-telling was examined in relation to theory of mind (first-order false belief understanding), executive functioning (measuring inhibitory control in conjunction with working memory), and presence of siblings in the home (no siblings vs. siblings; younger siblings vs. older siblings). Lie-telling was observed using a temptation resistance paradigm. Overall, of the 152 (74.9%) children who peeked at the toy, 73 (48%) lied during the temptation resistance paradigm. Children with higher scores on measures of first-order false belief understanding, and measures that relied on inhibitory control, were more likely to lie compared to their truthful counterparts. Additionally, children with older siblings were more likely to lie to the research assistant, and this relationship was independent of performance on cognitive tasks.Overall, results demonstrate that having an older sibling has an independent, direct effect on the development of young children's lie-telling abilities, irrespective of cognitive ability. These findings support the argument that lie-telling is a behavior that is facilitated by both cognitive and social factors.
K E Y W O R D Stheory of mind, deception, executive function, siblings