Why Kids Lie: What Their Brain Is Doing, and Why Punishment Backfires.
You ask if they brushed their teeth. They look right at you and say yes — and the toothbrush is bone dry, exactly where it was this morning.
What gets us in that moment usually isn't the untruth itself. It's how small the thing was, and how easily they could have just told us. And underneath the frustration, for a lot of us, there's a quieter worry — if they'll look me in the eye about a toothbrush, what happens when it's something that matters?
This post is the companion to this week's episode — a walk through what is happening in a child's brain when a lie shows up, where most of what the research has to say points somewhere gentler than we fear. By the end you'll have a way to tell two very different kinds of lying apart — and a handful of deposits you can make into your child's Trust Fund in the exact moment the lie is sitting there between you.
Is it normal for children to lie?
It's more than normal — the first real lie is a developmental milestone. A good one. Almost nobody says that to a new parent out loud.
Think about everything a child has to understand to tell a lie at all. They have to know that what's in their head is theirs — that you can't see it — and that they can place something in your head that's different from what they know to be true. That's theory of mind — the understanding that other people carry their own separate view of the world — and it comes online somewhere around age three or four.
There's a classic test for it, first run by Wimmer and Perner in the 1980s. A child watches a character — call him Max — tuck his chocolate into a blue cupboard and leave the room. While he's gone, someone moves it to the green cupboard. Then we ask the child where Max will look when he comes back. A three-year-old usually says the green cupboard — where the chocolate really is. They can't quite hold that Max still believes something that isn't true. But around four, children start pointing to the blue cupboard — where Max thinks it is. They can hold his belief in mind right alongside what they themselves know.
That exact ability is what a child needs in order to tell a lie. So when a young child looks at us and says something that plainly didn't happen, and does it badly, that isn't a crack in who they are. It's a new skill coming online, clumsy the way every new skill is clumsy at the start. We don't have to throw a party for the lie to let it mean something different than we feared — and that shift in our face and our voice is where everything that follows begins.
Are tall tales and imaginary friends the same as lying?
No — and the distinction matters, because if we treat the tall tale like the dry toothbrush, we can accidentally teach a child that something lovely about them is a problem.
I mean the child who announces, with total conviction, that there's a horse named Sunflower living in the backyard. Or who comes home and hands a friend a story grown three sizes taller than anything that happened. A lot of parents start to worry here — what if the stories end up costing them friends?
What's underneath the tall tale is a different thing from the cover-up. For a young child, the line between what's real and what's imagined is still being drawn. That sorting — this happened, this I made up — is a skill that develops across the preschool and early-school years, the same way counting or catching a ball does. Woolley and Ghossainy's work on the fantasy–reality distinction traces exactly this. A made-up story often isn't a calculated untruth at all. It's imagination narrated out loud, before the child has fully sorted which drawer it belongs in.
The same inventive current runs through imaginary companions, and the research there is reassuring. Marjorie Taylor's studies found that by around age seven, most children have had one at some point, and having one tends to travel with good things — often a step ahead at understanding how other people think and feel, and rich storytellers.
And usually the tall tale is doing a job. "I have a horse" is often just how a four-year-old says "I want a horse so much." Sometimes it's a reach for connection — something big and interesting to close the distance with a friend. When we can hear the wish underneath the story, we're hearing the true thing they're telling us.
So keep two honored kinds of telling in the house — things that really happened, and wish stories, the ones we make up because they're fun or because we wish they were true. Both are welcome; we just get to know which one we're in. "Ooh — is that a real story or a wish story?", asked with delight instead of suspicion, lets a child keep their whole inventive world and slowly learn to label it themselves. That's a deposit into their Trust Fund — the kind I call delight. Your particular mind is a joy to me. And there's validation folded in beside it — when we name the wish under the story, our child feels met at the exact place they were reaching from.
Why are children so bad at lying?
Because telling a lie takes more from the brain than telling the truth — not less.
Consider what the brain has to pull off. It has to hush the true answer, which is sitting right there wanting to come out. It has to invent a believable alternative on the spot. And it has to hold both versions in mind at once — the truth and the cover story — without letting them bump into each other. Those are three demanding jobs, and they all run on the same system — executive function, the brain's set of managing skills for impulse control, holding things in mind, and switching between them. In neuroimaging studies of adults — Christ and colleagues' meta-analysis of the deception research — telling a lie recruits those managing regions far more than telling the truth does, with the prefrontal cortex carrying the load. Truth is the low-effort default. A lie is the brain working overtime to override it.
That one fact explains the thing that drives us up the wall — how transparent the lie is, how it doesn't even line up with the evidence in plain view. A meta-analysis by Sai and colleagues, pooling dozens of studies of children's lying, found one of the clearest threads in this literature — a child's executive function is tied more to whether they can keep a lie going than to whether they tell one in the first place. Starting a lie is easy; it can slip out before the thinking part of the brain has caught up. Holding it together under a follow-up question is the hard part, and it's exactly the part a young brain can't quite do yet.
So the see-through lie — the one that comes apart the second you ask a second question — is a young brake still growing in, not a warning sign. This is one of the five AWAKE questions doing its quiet work, the one I call Knowledge — what does development tell me about what's happening here? And the shift in how we see it is itself a deposit — validation. When we read the falling-apart story as a brake that hasn't finished growing rather than a character we need to worry about, our voice softens, and our child feels that before we've said a word.
Is lying connected to ADHD?
Take that same brake and put it on a different clock — because for a child with ADHD, that's the situation.
The managing system we just walked through — the impulse control, the holding-in-mind — develops in the usual order in ADHD; it's just arriving later. Russell Barkley's foundational work reframed ADHD around exactly this, a lag in the brain's braking system that ripples out into the other managing skills. And there's brain imaging that grounds it. Shaw and colleagues followed children over years and found the ADHD brain reached its developmental markers in the cortex about three years later than peers, with the largest lag in the prefrontal cortex — the seat of impulse control and planning. The word that matters is later, not different. The same sequence, unfolding on a delay — and intelligence isn't part of the lag at all.
Put that next to lying and it lands softly. A child with ADHD is a little more likely to let a lie slip out, because the brake is slower — and a little less able to make it convincing, because holding a story together is the exact skill still on its way. The tumble-out, see-through lie is a younger brake doing its best in an older child.
There's one more piece here that's easy to miss. Sometimes what looks like a lie isn't one — it's memory. A recent study by Martin and colleagues — small, so we hold it lightly — found children with ADHD produced more false memories than their peers on a classic memory task, and were just as certain of the wrong memories as the right ones. At the kitchen table, that means "I did do my homework" can be an honest report of a memory that simply isn't accurate. Nothing is being covered up; their memory handed them the wrong picture, and they believed it.
The deposit here is validation, made in the practical moves. "Stop lying" becomes "let's check together." A shared system — a short checklist on the counter, a photo of the homework page — supports the memory that's still coming online, and it says the thing a child with ADHD almost never gets to hear — I can tell the difference between the wiring and the child.
Why does my child lie about things that actually matter?
So far we've been talking about the brake. There's another kind of lie, though, and it's the one that worries us most — the failed test hidden, the broken rule denied, the note from school that never makes it home. The child is old enough to know better, the brake works fine, and the lie still comes. When that happens, it's usually about one thing — how unbearable the truth feels to tell.
One of the most clarifying distinctions in psychology helps here — guilt versus shame. Guilt says "I did something bad." Shame says "I am bad." From the outside they look alike, but June Tangney's research traced them across the lifespan and they send a person in opposite directions. Guilt pulls toward repair — I want to make it right. Shame pulls the other way — toward hiding, disappearing, pushing the blame elsewhere, sometimes coming out swinging. Seen that way, a lie is often a shame-management move. The truth threatens the self, so the child buries it.
And for an anxious child especially — this is something I see often in my work, a clinical observation rather than a study finding — the lie is an escape hatch. Anxiety runs on anticipation. The child has already pictured the painful moment coming — the disappointment on your face, the conflict — so the brain grabs whatever makes that expected flood go away fastest, and a lie does exactly that. It works in the short run, which is why it comes back, and why it quietly blocks the one experience that would teach the child the truth was survivable. Fight, flight, freeze — and I'd add a fourth one, fib. The fib is a kind of flight. The child isn't running from you. They're running from the wave of shame or conflict they're braced for.
Which points straight at what helps. The deposit is regulation — ours, first. When our child hands us a hard truth and it meets a calm face and an even voice instead of the reaction they predicted, their brain records something it can use: I told the truth, and the disaster didn't come. Enough of those, and the math on lying quietly changes. We don't have to be perfectly calm — only a little steadier than the moment they feared.
Does punishing a child for lying teach honesty?
It's the question every parent lands on — and the research here is clear, and a little surprising.
In the study parents most need to know about, Victoria Talwar's team tempted a few hundred young children to peek at something they weren't supposed to, then asked them to tell the truth under different conditions. Some children were warned they'd be in trouble if they had peeked. Others were simply invited to be honest — told the grown-up would be glad, that telling the truth was a good thing to do. The threat of punishment didn't buy more honesty. What moved children toward the truth was the invitation — the sense that the truth would be met with warmth instead of danger.
There's an even sharper piece. When the two were combined — "please be honest"… and also "or you'll be in trouble" — children lied more, not less. The warning cancelled the invitation. Which hands us one line to keep for the hard moments: you cannot ask for the truth and punish it in the same breath.
And the pattern holds beyond the single moment. In a natural comparison, Talwar and Lee observed young children in two school settings — one where discipline ran harsh, one where it didn't — on the same honesty task. The children in the harsh setting didn't lie less. They lied more, and they lied better — their stories held together under questioning the way you'd normally only see in children years older. Harsh consequences didn't teach honesty. They taught skill at not getting caught, because the cost of getting caught had climbed so high.
Limits still matter. The spilled thing still gets wiped up; the rule still stands. What changes is that we pull honesty and consequences apart in time. The truth-telling gets met with safety, first and every time — "thank you for telling me," before the cleanup, before the conversation about what happened. The natural consequence of the thing itself can come later, once the child knows the truth didn't cost them us.
That separation is the deposit I call repair. A rupture, and then a reliable way back together. Edward Tronick's research with parents and infants found that ordinary interaction is full of mismatches — and that most of them get repaired in the very next step. What builds security isn't avoiding the rupture. It's the coming back, over and over. A child who learns that bringing us hard things has always been safe becomes the teenager, and the adult, who still brings us the hard thing.
When should I worry about my child's lying?
Most lying, even the frequent kind, is what we've walked through here — a young brake, a hard feeling, a wish said out loud. It softens as the brain grows and as the truth keeps turning out to be safe to tell.
If the lying becomes very frequent and travels with other things — a lot of aggression, a hardness toward others, a pattern that seems to be pulling your family apart rather than easing over time — that's worth bringing to a professional who can look closely alongside you. A child carrying that much distress deserves a closer look and some support, and so do you. Reaching out is its own kind of parenting.
Where to go from here
The full episode walks all of this in depth, with the at-the-kitchen-table language for each deposit.
If you'd like the deposits from this episode in one place, the Trust Fund Field Guide is the free companion download — a short walk through the deposits and how to keep making them.
Get the Trust Fund Field Guide →
And if you'd like the full framework behind the pause — Attachment, Wiring, Alignment, Knowledge, and Empowerment — that's the AWAKE Method course. Five questions that buy you a breath in the hard moments, built to help you see what you're already doing well.
Learn more about the AWAKE Method →
Nobody knows your child like you do. Every time a hard truth meets your steadiness instead of the reaction they braced for — that's a deposit. The Trust Fund grows.
— Dr. Kirsten Kuzirian, child psychologist
Research / Sources
The studies referenced in this post, for parents and clinicians who want to read further. Listed in order of appearance in the episode.
Wimmer, H., & Perner, J. (1983). Beliefs about beliefs: Representation and constraining function of wrong beliefs in young children's understanding of deception. Cognition, 13(1), 103–128. https://doi.org/10.1016/0010-0277(83)90004-5
Woolley, J. D., & Ghossainy, M. E. (2013). Revisiting the fantasy–reality distinction: Children as naïve skeptics. Child Development, 84(5), 1496–1510. https://doi.org/10.1111/cdev.12081
Taylor, M., Carlson, S. M., Maring, B. L., Gerow, L., & Charley, C. M. (2004). The characteristics and correlates of fantasy in school-age children: Imaginary companions, impersonation, and social understanding. Developmental Psychology, 40(6), 1173–1187. https://doi.org/10.1037/0012-1649.40.6.1173
Christ, S. E., Van Essen, D. C., Watson, J. M., Brubaker, L. E., & McDermott, K. B. (2009). The contributions of prefrontal cortex and executive control to deception: Evidence from activation likelihood estimate meta-analyses. Cerebral Cortex, 19(7), 1557–1566. https://doi.org/10.1093/cercor/bhn189
Sai, L., Shang, S., Tay, C., Liu, X., Sheng, T., Fu, G., Ding, X. P., & Lee, K. (2021). Theory of mind, executive function, and lying in children: A meta-analysis. Developmental Science, 24(5), e13096. https://doi.org/10.1111/desc.13096
Talwar, V., & Lee, K. (2002). Development of lying to conceal a transgression: Children's control of expressive behaviour during verbal deception. International Journal of Behavioral Development, 26(5), 436–444. https://doi.org/10.1080/01650250143000373
Barkley, R. A. (1997). Behavioral inhibition, sustained attention, and executive functions: Constructing a unifying theory of ADHD. Psychological Bulletin, 121(1), 65–94. https://doi.org/10.1037/0033-2909.121.1.65
Shaw, P., Eckstrand, K., Sharp, W., Blumenthal, J., Lerch, J. P., Greenstein, D., Clasen, L., Evans, A., Giedd, J., & Rapoport, J. L. (2007). Attention-deficit/hyperactivity disorder is characterized by a delay in cortical maturation. Proceedings of the National Academy of Sciences, 104(49), 19649–19654. https://doi.org/10.1073/pnas.0707741104
Martin, P., Speranza, M., & Colombel, F. (2025). Susceptibility of ADHD children to memory error production on a DRM task. British Journal of Developmental Psychology. Advance online publication. https://doi.org/10.1111/bjdp.70031
Tangney, J. P., Wagner, P. E., Hill-Barlow, D., Marschall, D. E., & Gramzow, R. (1996). Relation of shame and guilt to constructive versus destructive responses to anger across the lifespan. Journal of Personality and Social Psychology, 70(4), 797–809. https://doi.org/10.1037/0022-3514.70.4.797
Talwar, V., Arruda, C., & Yachison, S. (2015). The effects of punishment and appeals for honesty on children's truth-telling behavior. Journal of Experimental Child Psychology, 130, 209–217. https://doi.org/10.1016/j.jecp.2014.09.011
Talwar, V., & Lee, K. (2011). A punitive environment fosters children's dishonesty: A natural experiment. Child Development, 82(6), 1751–1758. https://doi.org/10.1111/j.1467-8624.2011.01663.x
Gianino, A., & Tronick, E. Z. (1988). The mutual regulation model: The infant's self and interactive regulation and coping and defensive capacities. In T. M. Field, P. M. McCabe, & N. Schneiderman (Eds.), Stress and coping across development (pp. 47–68). Lawrence Erlbaum Associates.
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