Why "No" Doesn't Work with Toddlers - It's How We Say It

I’ll be honest: when I became a mum, I thought I’d be pretty good at this.

After all, I’d taught hundreds of children over the years. I’d studied early childhood development to hone my craft. I knew what children needed. Surely, I’d have this whole parenting thing under control.

Then I had Brandon.

Suddenly, I wasn’t the calm, confident educator in a swim lesson. I was a mother in a messy home, a supermarket aisle, a family gathering - trying to get my very busy toddler to just put the spoon down, come to the table, get into the car seat, stop climbing onto furniture, stop unpacking the cupboards.

Sometimes, I’d hear myself saying it: “No.”And he’d hear it too. But not the way I thought.

I’ve learned the hard way — why “no” doesn’t work with toddlers has less to do with the word itself, and more to do with how their brains interpret it.

🧠 Why 'No' Doesn’t Work with Toddlers: The Brain Science Behind It

Here’s what I’ve learned - both from research and from living it.

Toddlers don’t process “no” the way adults do. For them, it isn’t an abstract moral statement; it’s just a sound. It only gains meaning when you wrap it in tone, body language, and emotion.

As Dr. Dan Siegel and Dr. Tina Payne Bryson explain in The Whole-Brain Child, young children interpret words through the emotional signals that surround them — facial expressions, body posture, and vocal tone — not just the words themselves.

A toddler’s emotional brain - the amygdala - is fully online from day one. It constantly scans for cues of safety or danger, especially in tone and body language.

Their logical brain - the prefrontal cortex, which manages self-control, cause-and-effect reasoning, and understanding rules - is still under construction. It won’t fully mature until their mid-20s.

Once I understood this, I realised why Brandon sometimes reacted so strongly. It wasn’t defiance; it was biology.

⚡ When Stress Switches Off Learning

Neuroscience tells us that stress interferes with learning.

When a child perceives a threat (even something as subtle as a raised voice or tense body), their stress hormones spike. Their nervous system shifts into fight, flight, or freeze mode.

In that state:

• Their ability to absorb new information plummets.

• Their focus shifts to self-protection, not understanding.

• They may stop the behaviour, but they don’t actually learn the lesson.

This is why fear might stop an action in the moment but rarely changes behaviour long-term.

The Center on the Developing Child at Harvard University notes that chronic or frequent stress activates the amygdala and suppresses the brain’s learning centers — particularly the prefrontal cortex, where reasoning and self-regulation live.

Knowing this made me see discipline differently. If my goal was to teach, not just control, I had to keep my child’s brain open to learning - not shut it down with fear.

🤲 The Lesson Isn’t the “No” - It’s You

When I slow down, crouch to his level, keep my voice steady, and guide his hands gently away from whatever mischief he’s in, he responds differently. He softens. He listens.

This isn’t about letting him do whatever he wants. I still hold boundaries. But the way I hold them shapes how he experiences them.

Research on co-regulation shows that children learn emotional regulation by experiencing it through their caregivers. When I stay calm, I’m not just keeping the moment peaceful; I’m showing him how to handle frustration, disappointment, and limits.

I’ve seen it in my swim classes too. Children learn far more when they feel safe than when they feel scolded. Safety isn’t just the absence of danger: it’s the presence of calm, consistent leadership.

🧩 Consistency Counts (Even When They’re Testing You)

The other day, Brandon tested a boundary with my husband. He got a firm “no” and immediately turned to look at me—maybe thinking Mum might give a different answer.

But we were on the same page. I backed my husband up with a quiet nod, and the testing stopped.

It wasn’t about overpowering him; it was about showing him that our words mean something. That the limit stands no matter who’s saying it. That he’s safe in knowing where the lines are.

🌱 What I’m Still Learning

I’ll be the first to say I’m not perfect at this. There are days when my tone is sharper than I’d like. Days when my patience wears thin. But I’ve learned that saying no to toddlers isn’t just about the word — it’s about how we show up in that moment. My power as a parent isn’t in always getting it right; it’s in trying again. In repairing when I mess up. In showing Brandon that kindness and firmness can live in the same breath.

Experts like Dr. John Gottman describe “emotional repair” — reconnecting after conflict — as one of the most powerful forms of relationship building. The rupture isn’t the problem. It’s how we come back.

When I first became a mum, I thought “no” was enough.

Now I know better—it’s not the word.

It’s the way I show up when I say it.

💬 Your Turn

Think about the last time you said “no” to your child. What did your tone, your body language, and your follow-through say?

Because maybe it’s not just toddlers who respond to that. Maybe it’s all of us.

References

Center on the Developing Child at Harvard University. (n.d.). Serve and return. Harvard University. https://developingchild.harvard.edu/key-concept/serve-and-return/

Gottman, J. M., & DeClaire, J. (1998). Raising an emotionally intelligent child. Simon & Schuster.

Hamoudi, A., Murray, D. W., Sorensen, L., & Fontaine, A. (2015). Self-regulation and Toxic Stress: A Review of Ecological, Biological, and Developmental Studies of Self-regulation and Stress. In Policy File. Sanford Institute of Public Policy, Duke University.

Siegel, D. J., & Bryson, T. P. (2013). [Rev. of The Whole-Brain Child: 12 Revolutionary Strategies to Nurture your Child’s Developing Mind]. The International Journal of Childbirth Education, 28(4), 83.