“No” Isn’t Personal: Understanding Behaviour in Children Under 5

Life with a young child can feel emotionally demanding in ways
that are hard to explain to others.

There are days when you repeat the same words again and again, watch rules collapse in seconds, and wonder how a child who clearly understands can suddenly seem unable to cooperate. In those moments, frustration often mixes with doubt. Parents may ask themselves whether they are doing something wrong, being too strict, too soft, or simply missing something important.

Much of this experience, however, reflects the reality of early childhood development rather than a problem with parenting or a child’s attitude.

When Behaviour Feels Confusing

In everyday life, behaviour in children under five can look inconsistent and unpredictable. A child may refuse a request they followed earlier, test limits they already know, or move rapidly between cooperation and resistance. The same child may behave calmly in one setting and struggle intensely in another, even when expectations remain unchanged.

For parents, this can feel personal. It can feel as though the child is pushing back deliberately or choosing when to listen. Yet from a developmental perspective, these patterns are common and expected at this age. They reflect a system that is still learning how to manage itself in real time.

What Is Still Growing Beneath the Behaviour

Between the ages of three and five, children are still developing the brain systems that support self-control. These systems help a child pause before acting, keep rules in mind while doing something else, and adjust behaviour when situations change. Although these abilities begin to emerge early, they are not yet stable or reliable.

From the child’s perspective, this can be confusing as well. A child may know a rule and still find themselves acting against it moments later. This mismatch between understanding and behaviour is not experienced as defiance. It is experienced as difficulty, a sense that things fall apart faster than they can be held together.

Why Behaviour Shifts So Quickly

Behaviour in early childhood is shaped by more than effort or willingness. It reflects limited control, limited capacity to process information, and a high sensitivity to context. When children are tired, overstimulated, or faced with multiple demands at once, access to control can drop quickly.

In these moments, rules may be understood but not easily applied. Behaviour may change rapidly, sometimes without warning. For parents, this sudden shift can feel baffling or exasperating. For children, it often feels overwhelming rather than intentional.

What looks like a choice from the outside is often a reflection of what the system can manage in that moment.

What Helps Behaviour Hold Together

Research consistently shows that young children practise emerging self-control best in environments that are clear and predictable. Consistency helps because it reduces the amount of processing required. When the same rule is communicated with the same words, when expectations are introduced one at a time, and when adults pause rather than escalate, children are better able to use the skills they are still developing.

Equally important is recognising when a child’s system is tired or overloaded. Allowing space for rest does not mean removing boundaries. It means acknowledging that capacity fluctuates, and that behaviour is more likely to fall apart when demands exceed what the child can currently manage.

A Shared Experience

Understanding early childhood behaviour does not make parenting effortless. It does not remove frustration, fatigue, or moments of doubt. But it can soften how those moments are interpreted.

For parents, this understanding can ease self-blame and reduce the sense that every difficult interaction is a personal failure. For children, it creates space to practise skills that are still under construction, within relationships that remain steady even when behaviour wobbles.

Behaviour under five is not a statement of character. It is a snapshot of development in progress.

*This post is dedicated to the little rascal of our family the Boss Under 5 in our home.*

References

Cuevas, K., & Bell, M. A. (2015). Developmental changes in executive function during early childhood. Developmental Psychobiology, 57(7), 899–911.

Zelazo, P. D., Blair, C. B., & Willoughby, M. T. (2016). Executive function: Implications for education. Psychological Science in the Public Interest.