Lying and Child Development

Lying and Child Development

Hello brave parents and caregivers,

Though lying is very common in childhood, it is understandably a source of stress for both parents and children. It can be helpful to realize that lying is often more a reflection of a child’s cognitive ability than an intentional moral violation, particularly in the early years.

Lying is a complex task that requires the development of several important cognitive capacities. In fact, lying in the preschool years is recognized as a key developmental milestone.

So, before we jump to conclusions about the character of our beloved (and occasionally lie-telling) kids, let’s take a closer look at lying and child development.

Lying and Cognitive Abilities

There are two main cognitive capacities that children need to develop in order to tell a lie.

1. Theory of mind

This means to understand:

  1. That you can have thoughts or beliefs that are different from reality
  2. That people may not have the same thoughts and feelings that you do
  3. How to take another person’s perspective

2. Executive functioning

A group of brain abilities involving:

  1. Inhibitory control–to control what you say or do
  2. Working memory–to hold information in your mind so you can recall it later
  3. Planning–to work out the steps needed to achieve a goal

2-4 Years Old

By 2-3 years old, children start to develop theory of mind–they realize that they can have a thought that is not true to reality and that other people may not realize they are not telling the truth.  This sets the stage for lying. At this age, lies usually involve children concealing that they have done something they were not supposed to do. Often, the lies are highly unrealistic (e.g., “I didn’t draw on the floor, it was the cat!”). And though children are able to produce lies at this age, they usually do not have the executive functioning skills to keep a lie going. For instance, even after just blaming the cat, if you asked a follow-up question about why they chose the green crayon to draw on the floor, they may respond with, “Because it’s my favorite color!”

Keep in mind that lies in this age group may also stem from wish fulfillment or from pure imagination. A child may, for instance, claim she did not hit her sibling because she wishes she hadn’t. Or, in the case of my daughter, recount detailed stories of swimming with her teachers and friends during her 2-year-old (entirely pool-less) school program. Definitely not true, but I can see how she might like to imagine having had such a fun adventure at school.

4- 5 Years Old

By this age, children are able to consider another person’s beliefs or knowledge when telling lies. Taking the previous example, they may now take into account that their parents know that cats cannot draw and so they tell a more realistic lie (e.g., “I didn’t draw on the floor, my brother did!”).

6- 8 Years Old

Children now understand that once they have told you a lie, that, to remain convincing, you expect them to respond in a way that is consistent with the lie. Correspondingly, they may now be able to keep their initial lies going. As in the above example, if you asked a child in this age group why she chose a green crayon to draw the floor, she may respond with: “I didn’t use any color crayon to draw on the floor because I didn’t do it!”

Advancing executive functioning skills also make it easier to maintain lies. Cognitively, children are more able to control what they say, remember the lie they told and stay consistent with it, and plan how they will respond. Hold onto your seats, they may really be able to pull the wool over your eyes at this point.

8 Years Old- Adolescence

Lying is not always straightforward, is it? Sometimes we tell lies not to hurt someone’s feelings. While lying in early childhood is usually related to concealing a transgression, as children get older, they develop the capacity to tell so-called prosocial lies, or lies intended to benefit others (e.g., to protect his feelings, telling a gift-giver you like his gift of the LEGO set you already own). By this age, children have developed the capacity to take another person’s perspective and can take into account how he may feel about hearing the truth. By about 9 years old, prosocial lying usually outweighs lying to conceal a misdeed.  

Keep in mind that though children have a basic sense of right and wrong by about 3-6 years old, it’s not until early adolescence that they are mature enough to really consider the moral implications behind telling a lie.

Brave parents and caregivers,

The truth is that lying in childhood is common. And as a child’s cognitive abilities grow, as does her capacity for lying.  My hope is that by improving our understanding of lying and child development, we can reduce shame and judgement when it comes to approaching our kids’ lie-telling.

At the same time, I realize you may be thinking this is all well and good, but we don’t want our children to lie (in most cases). I hear you. Lying is such a complex and pervasive issue, my next couple posts will focus on digging deeper into childhood lying.

So, stay tuned as I explore the reasons why children lie, lying and parenting style, lying and ADHD, red flags for problematic lying, and, importantly, how to approach lying with your child.

Until next time,  


  1. Talwar V and Lee K (2008). Social and cognitive correlates of children’s lying behavior. Child Development. 79 (4), 866-881.
  2. Lee JYS and Imuta K (2021). Lying and theory of mind: A meta-analysis. Child Development. 92 (2), 536-553.
  3. O’Connor AM, Dykstra VW, Evans AD. Executive functions and young children’s lie-telling and lie maintenance. Developmental Psychology. 56 (7), 1278-1289.

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