We don’t have three brains – find out more about your toddler’s brain

If you’ve ever googled brain development you might have come across articles that refer to the triune model of the brain, or that describe us as having a lizard brain which takes over when we feel scared or threatened. As neuroscientists learn more about our brains, this way of understanding the brain has been questioned – read on to find out more.  

We don’t have a lizard brain 

The triune model is based on the theory that our brains are split into three parts, each of which has a very specific role. This comes from an evolutionary theory – suggesting that as humans evolved our brains became more complex, with areas for cognition developing separately to areas focused on survival.  

In the triune theory of the brain, scientists suggest we have separate areas of the brain linked to basic behaviours, emotions and thinking.   

Now, scientists have found that our brains did not evolve in stages like this – with new areas of the brain developing on top of older areas creating a lizard brain, mammal brain and human brain. In fact, all vertebrates share a similar brain structure – although each area is different according to the animals’ needs.^[1] 

Areas of our brains work together  

The triune theory of the brain suggests that these separate areas of the brain function independently – so we have an emotional area of the brain. But now neuroscientists know that areas of the brain are in fact interconnected and work closely together – there is no separate emotional area.  

Why it's helpful to think differently about our brains – adapting to the world 

Understanding areas of our brains as interconnected can help us to think about how our brains change and adapt according to experiences.  

A different way of understanding our brain is to view it as always active, with areas working together to keep us in a balanced state – so, not too alert or too calm, not too hungry or too full, and so on.  

Your toddler’s brain is changing and developing with each experience 

This explanation doesn’t mean that what you’ve read about your toddler not being able to control their emotions is wrong. Rather, that the explanation about why is slightly different to what you might have read.  

When you think about feeling scared, sad or angry you recognise that your body responds to these situations – your pulse rate might increase, your stomach might feel strange.  

Your brain’s job in these situations is to respond and take action to make sure you’re safe then restore balance – your toddler’s brain has not had as much practice doing this as yours and so they will find it harder.  

When your toddler becomes upset, frustrated or angry, their brain recognises the response their body is having to a situation – they know they don’t feel right but don’t know what to do about it! 

If these feelings then lead to more unpleasant experiences, perhaps being shouted at or isolated – next time your toddler’s brain will expect the same outcome. So, when that situation happens again their brain predicts a negative experience and might reinforce feelings of sadness, anger or fear.  

When you respond calmly – and show your toddler how to recognise the physical and emotional response they are having – you not only help them to calm, but also help them to predict that more positive outcome in future.  

You are (with lots and lots of repetition) helping them to connect how their body feels in a situation with their emotions and an understanding of what has happened – with lots of repetition this helps them to recognise their emotions and respond to them. 

You could say, you’re helping to wire their brain for calm.   

Reference: 

[1] Steffen, P.R., Hedges, D., & Matheson, R. (2022). The brain is adaptive not triune: How the brain responds to threat, challenge, and change. Frontiers in Psychiatry