Why Children Lie: Research Says It Is a Normal Part of Brain Development

Many people assume children cannot lie. Reality and science say something quite different. Children can lie, and being able to lie is part of their normal mental development. Some children begin lying from as early as age two, and by after age four most children have learned to lie.

This is no idle claim. Psychologist Kang Lee of Canada’s University of Toronto and his colleagues ran an experiment on the question. Several children were placed in a room and told a toy had been kept behind them but they must not look at it. Each child was then left alone while a hidden camera watched whether they peeked. Afterwards they were asked whether they had seen the toy.

The study found that 30 percent of two-year-olds, about 50 percent of three-year-olds and about 80 percent of children aged four and above lied. Interestingly, young children who lie are very easily caught — a child may say “No, I didn’t see it” and in the next moment blurt out the toy’s name or describe what it looks like. As they grow older, however, they learn to invent stories of their own.

Although a child’s lying may look ordinary on the surface, remarkable science lies behind it. Telling the truth is fairly easy, because one only has to say what happened. Lying, however, requires the brain to do many things at once, and for children it is a real skill.

To lie, a child must first remember the actual truth; not only remember it, but carefully hold it back. Then the child must understand another person’s mind and position before lying. Inventing a new story and, while controlling their own emotions, presenting that story convincingly to someone else is no ordinary task for a child. For exactly this reason, scientists regard children’s lying as a high-level mental skill.

The first driving force behind this lying is the child’s cognitive understanding and the development of thought. How a child thinks, remembers, learns new things, solves problems, uses language and understands others’ minds — the gradual improvement of this whole process is called cognitive development. Put simply, a child’s brain is like a computer: at birth the machine is in place, but the software inside is very basic; with age, new “apps” such as memory, language and reasoning are added.

According to psychologist Erik Erikson, the central conflict for children aged three to six is between initiative and guilt. At this age a child wants to do many things on their own and to prove themselves among adults. But they cannot yet fully understand which actions are right and which are wrong. A child may want to pour water from a jug into a glass, or draw a picture on the wall for fun. But if the water spills and floods the room, or they are scolded for drawing on the wall, they realise the act was wrong and feel shame and guilt.

In such a situation, the child raises lying as a shield to save themselves from a scolding. In other words, what we think of as ordinary lying is actually a kind of exercise of the child’s executive function. In telling that lie, the child unknowingly practises their thinking power, sense of duty and self-control.

Swiss psychologist Jean Piaget, on the other hand, held that a child’s thinking develops through several distinct stages. He called the period from age two to seven the pre-operational stage. Lying at this age is mainly linked to three things. First, a powerful imagination: a child may genuinely believe a fairy is hiding under their pillow, or that a colourful fairy world exists in the land of clouds. What adults see as a lie may, for the child, be a wonderful imaginary world of their own creation.

Second, as experience grows, a child develops a viewpoint of their own; this is called egocentrism. Children then begin to think that what they know, everyone else knows too. Sometimes they think the opposite — many children believe that if they close their own eyes, nobody outside can see them. Third, children cannot fully grasp the future consequences of their actions or words. Compared with the far-off thought “if I lie I might get caught later”, the question “how do I escape this scolding right now” feels far more urgent to them.

Beyond lies of imagination or lies to escape punishment, children’s lying has several other faces. Many children lie to attract adults’ attention; others lie to show off — “I came first in the race!” or “There is a tiger and a bear at my house!” Many children also learn “white lies” by watching their parents: even if a birthday gift was not liked at all, they politely say, “The gift is very beautiful!”

It becomes a matter of concern when a child begins lying repeatedly, habitually and without reason. In such cases, researchers believe parents need to pay special attention to the child’s behaviour.

Children naturally seek safety at all times. If telling the truth feels safe to them, they tell the truth with ease. And if telling the truth wins adults’ attention or praise, children keep up the habit of truthfulness. Harsh punishment or excessive discipline, on the other hand, does not reduce children’s lying at all; as they grow older it instead teaches them to hide their faults better. When afraid, the cognitive side of the brain strengthens the urge to escape punishment, and the child takes refuge in more polished lies to save themselves. So to reduce lying, the environment for telling the truth must first be made safe and respectful for every child.