Development of lying to conceal a transgression: Children's control of expressive behaviour during verbal deception

The present study examined lying behaviour in children between 3 and 7 years of age with two experiments. A temptation resistance paradigm was used in which children were left alone in a room with a music-playing toy placed behind their back. The children were told not to peek at the toy. Most children could not resist the temptation and peeked at the toy. When the experimenter asked them whether they had peeked, about half of the 3-year-olds confessed to their transgression, whereas most older children lied. Naive adult evaluators (undergraduate students and parents) who watched video clips of the children's responses could not discriminate lie-tellers from nonliars on the basis of their nonverbal expressive behaviours. However, the children were poor at semantic leakage control and adults could correctly identify most of the lie-tellers based on their verbal statements made in the same context as the lie. The combined results regarding children's verbal and nonverbal leakage control suggest that children under 8 years of age are not fully skilled lie-tellers.