You’re getting their after-school snack ready and you ask if they’ve done their homework. They say yes. An hour later you find out they haven’t even opened their school bag. A small lie, not a big deal. But it isn’t the first time. Your child keeps lying, and you’ve started to notice.
And there are days when the lie is more serious. They look you in the eye and tell you something you know perfectly well isn’t true. Calmly. In detail. And then the question changes. It’s no longer “why did they do that?” The question is: what’s going on inside them that they’d rather lie to me?
The short answer: because at that moment it seems like the safest option. The long answer is much more interesting, and it changes quite a lot about how you’ll react next time.
Because if there’s one thing research shows clearly, it’s that the usual parental reaction to lying doesn’t produce honesty. In many cases, it produces better lies.
Before you get angry: what science says about why children lie
The researcher Victoria Talwar, director of the Child Development Lab at McGill University (Canada) and Canada Research Chair in Forensic Developmental Psychology since November 2024, has spent decades studying how and why children lie. One of her most counterintuitive conclusions: a child who lies well isn’t a warning sign. It’s a sign that their brain is working as it should.
To lie, a child has to understand that you don’t know what they know. That takes what psychologists call theory of mind: the ability to put yourself in someone else’s place and understand that they have thoughts, beliefs and knowledge different from yours. This ability develops between the ages of 3 and 5.
The researcher Kang Lee, of the Institute of Child Study at the University of Toronto, documented that by the age of 4, 90% of children already know how to lie. At 2, 20% can do it regularly. Not because they’re bad. But because their brain has reached the level of cognitive development needed to understand that other people don’t see what they see.
That doesn’t mean you should ignore the lie. It means that before reacting, it’s worth asking yourself: what is this lie for, right at this moment?
Why your child lies at this age (and what it really means)
Children aged 8 to 12 lie mainly for four reasons. And recognising which is which completely changes how to respond.
To avoid consequences. This is the most frequent lie and, deep down, the most understandable. The child calculates, even if only by instinct, that lying costs less than telling the truth. If the truth is normally met with a shout, a telling-off or a punishment, that calculation isn’t entirely wrong. It’s survival logic.
To keep a space of their own. From around 8 or 9, children start to separate their world from the adult world. When a lie is about this, what they’re often doing is testing how much room they have to be themselves without you examining everything. There’s no bad intention. It’s autonomy developing.
So as not to disappoint you. This is the one that hurts most, because behind it is a child afraid of not living up to what they imagine you expect. They aren’t lying out of cheek. They’re lying because they care what you think of them.
The prosocial lie. Sometimes children lie to protect someone, a friend, a sibling, you, from something they think would hurt them. It carries a completely different moral weight, and it deserves a different conversation.
The three traps that make children lie more
After discovering a lie, parents tend to fall into one of these:
Trap 1: The interrogation. The more direct questions you ask, the more a child digs in. Pressure doesn’t produce truth. It produces better-constructed lies for next time.
Trap 2: The disproportionate reaction. If every lie means a crisis at home, the child does the sums: telling the truth costs a great deal. And they’ll keep deciding to lie.
Trap 3: The comparison. What a child hears isn’t that they should be more honest. What they hear is that they don’t measure up. And that doesn’t build honesty. It builds shame.
A systematic review published in the Journal of Family Theory & Review (2024) found that adults who were punished more for lying as children did not become more honest. In many cases, they learned to lie more skilfully so as not to be found out.
What really works when your child lies
Take a moment before reacting. You don’t have to respond in the second you discover the lie. What you do in the first five seconds will decide whether your child learns that the truth is viable or that lying was the right call.
Talk about the lie, not the child. “What you told me isn’t true” is different from “you’re a liar”. The first points to a behaviour. The second points to an identity.
Leave a door open for the truth. “If there’s anything you’d like to tell me differently, you can. I’m listening.” This builds a channel for the truth to arrive, now or later.
Name what you imagine is behind it. “I think you were afraid of what would happen if you told me.” If you’ve got it right, your child feels seen. If you haven’t, they’ll correct you, and in doing so, they’ll be telling you the truth.
Show how truth works in practice. When you make a mistake and own up to it out loud, you’re teaching something no lecture can get across: that admitting the truth doesn’t destroy anyone.
Honesty isn’t taught with lectures: it’s practised
You can explain to your child a thousand times why lying is wrong. They can repeat your arguments back to you by heart. And carry on lying.
Not because they don’t understand. But because understanding isn’t enough. Honesty is a skill that gets practised in real situations, with real consequences, in a setting where being honest makes sense.
What builds honesty isn’t speeches. It’s the repeated experience that telling the truth is viable. That when you do it, the adult in front of you doesn’t destroy you. That the cost of being honest is lower than the cost of lying.
This is exactly what Rolin works on: game situations where children make decisions that have consequences inside the adventure, and where acting honestly has value because they’ve lived it, not because someone explained it.
If you’d like to see how it works, the free guide is a good place to start.