Children’s Faces Reveal Differences Between Antisocial and Prosocial Lies

What is it about?

Children sometimes lie for very different reasons. They may tell an antisocial lie to hide something they did wrong, or a prosocial lie to avoid hurting someone’s feelings. This study examined whether children’s facial expressions differ when telling these two types of lies. Researchers studied 57 children between 6 and 11 years old. Some children were asked not to peek while a gift was being wrapped, but peeked anyway and then denied doing so. Other children received an undesirable gift—a bar of soap—and politely claimed that they liked it. A computer program called the Computer Expression Recognition Toolbox (CERT) measured subtle facial expressions immediately before the children gave their answers. Using this facial-expression information, machine-learning models could distinguish between antisocial and prosocial lies at rates significantly above chance. Children showed more joy when telling prosocial lies than when telling antisocial lies. Three specific facial movements—lip puckering, blinking or eye closure, and raising one side of the upper lip—also helped distinguish the two types of lies. Gender differences were found during prosocial lying: girls showed more joy and less contempt than boys.

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Photo by Austin Pacheco on Unsplash

Photo by Austin Pacheco on Unsplash

Why is it important?

The findings show that children’s facial expressions are not the same across different kinds of lies. Instead, children appear to adjust their facial behaviour to fit the social context of the lie. For example, pretending to like an unwanted gift involves different expectations about how a child should behave than denying that they did something they were told not to do. The study also shows that computer technology can detect subtle differences in children’s facial expressions that may be difficult and time-consuming for human observers to measure. This gives researchers a new way to study how children learn to manage their emotional expressions in different social situations. Importantly, the study compared two different kinds of lies; it did not compare lying with truth-telling. Therefore, the findings do not show that these facial expressions can be used as general signs that a child is lying.