Understanding Big Emotions in Children Aged 0–5

If you’ve ever watched a two-year-old have a complete breakdown over the wrong colour cup, you’ve witnessed something that makes a lot more sense when you understand what’s happening in the developing brain.

Young children don’t have big emotions because they’re difficult. They have big emotions because they’re human, they’re young, and their brains are in the most rapid developmental period of their entire lives.

The situation

Your child aged 0 to 5 experiences emotions that seem disproportionate — fear of ordinary things, rage over small disappointments, joy that tips into overstimulation, grief over minor losses. You want to understand what’s happening — and how to respond in a way that helps them develop emotional health, not just get through the moment.

What’s happening in the developing brain

At birth, the brain is only about 25% of its adult size. The emotional centre of the brain — the limbic system — is present and active from very early on. But the part of the brain responsible for regulating those emotions — the prefrontal cortex — won’t be fully developed until the mid-twenties.

This means young children feel everything fully, immediately, and with enormous intensity — but have very limited ability to manage, moderate, or make sense of those feelings on their own. They are, in the truest sense, dependent on the adults around them to help regulate their emotional experience.

This is called co-regulation — and it’s not a parenting choice. It’s a biological need.

Emotional development by age

0–12 months: Babies experience emotions (comfort, distress, interest, joy) but have no ability to self-regulate at all. A parent’s calm presence is the only source of regulation available to them. This is why responsive caregiving in the first year is so significant.

1–2 years: Toddlers begin to experience more complex emotions — frustration, pride, jealousy — and have a strongly developing sense of self and will. Language is emerging but still limited. The gap between what they feel and what they can express is enormous, which is a major source of frustration and meltdowns.

2–3 years: The classic “terrible twos” reflect a child whose sense of autonomy is expanding rapidly while their self-regulation is still very underdeveloped. Tantrums are at their peak in this period. This is developmentally normal, not a sign of a problem.

3–5 years: Language and emotional vocabulary are growing. Children at this age can begin to name feelings, understand simple cause and effect, and participate more in problem-solving — with support. They’re starting to develop empathy and a rudimentary understanding of others’ feelings.

What helps emotional development

• Naming feelings. When you say “you’re frustrated” or “that made you really sad,” you help your child build an emotional vocabulary and give shape to experiences that would otherwise just feel overwhelming.
• Staying regulated yourself. Your nervous system is the external regulator. When you’re calm and present, your child can borrow that regulation. This is not always possible — but it’s one of the most powerful things you offer.
• Allowing feelings without rushing to fix them. Emotional development happens through the experience of having feelings — not through having them removed quickly. Allowing your child to feel upset (with you present) builds resilience and emotional intelligence.
• Consistent, predictable responses. Children develop emotional security when they know that big feelings won’t destroy the relationship — that you’ll still be there, still warm, still safe, after the storm passes.

A quick summary

Big emotions in young children are not a behaviour problem — they’re a developmental reality. The brain’s emotional systems are active and powerful long before the regulatory systems that manage them. Understanding this shifts the parenting question from “how do I stop this feeling?” to “how do I help my child through this feeling?” — and that shift changes everything.