If you have ever wondered why your child cannot just calm down, why they seem to know better but still do the same thing again, or why your teenager appears perfectly rational one moment and completely irrational the next, the answer is almost always the same.
Their brain is not finished yet.
This is not an excuse. It is a biological reality that changes everything about how we understand children’s behaviour, and how we respond to it.
The brain is not fully developed until twenty five
This surprises most parents. We tend to assume that by the time a child looks grown, they are grown. But the brain develops from the back to the front, and the very last part to mature is the prefrontal cortex, the region responsible for decision making, impulse control, planning, empathy, and understanding consequences.
That process is not complete until around the age of twenty five.
This means that from birth right through adolescence and into early adulthood, children are operating with an incomplete brain. Not a broken one. Not a bad one. An incomplete one. And understanding that reframes almost everything.
The two key players: the amygdala and the prefrontal cortex
To understand your child’s behaviour, it helps to know about two key brain regions.
The amygdala is the brain’s alarm system. It is ancient, fast, and designed for survival. It detects threat in a fraction of a second and triggers the fight, flight, or freeze response before the thinking brain has even registered what is happening. In children, the amygdala is fully operational from very early on. It is always on duty.
The prefrontal cortex is the brain’s wise elder. It can pause, reflect, consider consequences, manage impulses, and override the alarm. However it is the last part of the brain to develop and the first to go offline under stress.
This is why a child who knows perfectly well that hitting is wrong will still hit when they are overwhelmed. The knowing and the doing come from different parts of the brain, and in a moment of high emotion the amygdala is driving, not the prefrontal cortex.
You can read more about this in my free guide Understanding Your Child’s Guard Dog Brain.
The developing brain from birth to adulthood
Birth to two years
In the first two years of life the brain is growing faster than at any other point. A baby is born with around 100 billion neurons but very few connections between them. Every experience, every interaction, every moment of being held, soothed, seen, and responded to, builds new neural pathways.
This is why early relationships matter so much. The repeated experience of distress followed by comfort, of need followed by response, builds the architecture of the developing brain. It literally shapes the structures that will underpin emotional regulation, attachment, and stress response for the rest of life.
Two to seven years
This is a period of enormous cognitive and emotional development. Language is expanding rapidly. Imagination is vivid and the line between real and pretend is not yet clear. Children at this age are just beginning to develop the capacity for emotional regulation, but it is fragile and inconsistent.
Executive functioning skills, the ability to plan, organise, shift between tasks, and control impulses, are beginning to emerge but are nowhere near reliable. This is why a five year old who knows the rule can still break it. The prefrontal cortex is simply not developed enough yet to consistently override the pull of the moment.
Tantrums, meltdowns, and big emotional reactions at this age are not bad behaviour. They are a developing nervous system doing its best with the tools it has.
Seven to twelve years
The middle childhood years bring greater emotional stability for most children. The prefrontal cortex is developing and children become more able to reason, plan, and manage their impulses. They develop a clearer sense of self, of fairness, and of social rules.
However this is also the period when anxiety often becomes more specific and more cognitive. Children are old enough to understand that real dangers exist in the world but not yet old enough to hold that knowledge without worry. And when stress is high, the prefrontal cortex still goes offline and the amygdala takes over.
Twelve to twenty five years
Adolescence brings the most dramatic brain reorganisation since the first two years of life. The brain prunes unused neural connections and strengthens the ones it uses most. This pruning starts at the back of the brain and works forward, with the prefrontal cortex being the last to be remodelled.
During this period teenagers rely heavily on the amygdala when making decisions, particularly under stress or in social situations. Combined with heightened dopamine activity, which drives pleasure seeking and risk taking, this explains much of the behaviour that parents find so challenging.
Furthermore the adolescent brain is exquisitely sensitive to social threat. Being excluded, embarrassed, or judged by peers activates the same threat response as physical danger. This is not drama. It is neuroscience.
You can read more about the teenage brain and how to navigate this period in my blog Surviving the Teenage Transition.
How early experiences shape the developing brain
The brain does not develop in isolation. It develops in relationship. The quality of a child’s early caregiving environment shapes the developing brain in profound and lasting ways.
Research into adverse childhood experiences, known as ACEs, has shown that children exposed to significant stress, neglect, or trauma in their early years develop differently. The stress response system becomes more sensitised. The amygdala is more reactive. The prefrontal cortex has less capacity to regulate.
This is not a life sentence. The brain is remarkably plastic and positive, responsive caregiving can mediate the effects of early adversity at any stage. But it does explain why some children find regulation so much harder than others, and why those children need more support, more consistently, for longer.
You can read more about this in my blog Why Does My Child Struggle with Emotional Regulation.
What this means for how you parent
Understanding the developing brain does not lower the bar. Children still need boundaries, consistency, and clear expectations. However it changes the frame from which you set those boundaries.
Instead of why are you doing this when you know better, the question becomes what does my child need right now to help their developing brain learn to manage this differently.
Instead of punishment that shames or frightens, which activates the amygdala and shuts down the prefrontal cortex, we look for responses that keep the relationship safe and teach rather than simply punish.
Instead of expecting adult level regulation from a child whose brain is not yet capable of it, we co-regulate, lending our calm nervous system to theirs until they can find their own.
This is the heart of authoritative parenting. You can read more about why it works in my blog Authoritative Parenting: The Most Effective Parenting Style.
When to seek support
If your child is struggling significantly with emotional regulation, behaviour, anxiety, or learning, it is always worth seeking support. The developing brain is most responsive to intervention early. Waiting to see if they grow out of it is sometimes the right call. But if difficulties are significant and persistent, earlier support is always better.
If you would like to talk through what is happening for your child, please do get in touch via my contact page.
Free resources
Understanding Your Child’s Guard Dog Brain explains the amygdala and threat response in accessible language for parents.
Holding in the Storm is about staying steady as a parent when the developing brain is doing its loudest work.
Both are free to download.
And if you would like occasional guidance and support straight to your inbox, you are very welcome to join my newsletter.
With warmth,
Catherine
