Building Your Baby’s Brain

by Jemma Munford

In the early years, our children’s brains are going through a huge amount of change. They are born with only around 30% of an adult’s brain. They can manage a very limited number of skills but even then, still solely rely on the parent to ensure they are able to survive the first weeks and months. By the end of the first year the brain has doubled in volume, and by 5 years is 90% the volume of an adult brain.


The human brain is amazing, through experience and repetition it makes more and more connections inside and learns and grows. In the early years, it develops faster than any other time in our lives.


A baby’s brain is born with almost as many neurons as it will ever have – around 100 billion! It also produces trillions more neurons and synapses (which are the connections between cells) than it will ever need. 


In normal brain development, over the first few years of life the brain will strengthen some of these connections and will discard (prune) the ones that are rarely used.


The first 1001 days (which is pregnancy to the first two years of your child’s life) are critical to brain development. How you respond and care for your baby during this period will shape how their brain works for the rest of their life. Being responsive and taking care of your baby’s emotional as well as physical needs helps their brain to grow and helps them to be more resilient to conditions like anxiety and depression and even asthma and ADHD.


Your child’s experiences whether they are good or bad have direct impact on how the brain is wired forever. Positive and loving experiences with caregivers stimulates growth in the synapses and for those existing connections to become stronger and stronger. If a child is not stimulated, those connections will be pruned and lost.


We can support healthy brain development by helping our children cope with stress, by being responsive and attuned to their needs and providing positive stimulation and opportunity for play.

Stress and Brain Development

Parents play an important role in helping children learn how to cope with stress. This is an important part of childhood development. 


In infancy, the brain is super sensitive to external influences, and repeated exposure to long term stress can increase the sensitivity of the neural circuits that process threat information which can result in hyper-sensitivity to stress in later life. Stress and anxiety can impact sleep (read more about that here).


In a stressful situation, our body responds by increasing our heart rate and blood pressure and releases stress hormones such as cortisol. How long and how frequently that reaction persists affects the brain. 


We can reduce and neutralise some of the effects of stress by protecting and supporting children through these experiences.


Positive stress response is part of normal and healthy life experiences such as starting nursery for the first time or even performing in a school play for example. It results in higher heart rate and a mild increase in stress hormones.

Tolerable stress response occurs when they experience something frightening such as a loved one dying or witnessing an accident. This elicits a stronger response than positive stress, but when this is buffered through the support of their primary caregivers, the body recovers more quickly and long-term damage is avoided.

Toxic stress response is a prolonged state of stress from on-going or repeated hardship. This might be from abuse (physical or emotional), neglect or economic hardship where the adult support offered is either not there or insufficient. Toxic stress has a direct impact on the structure of the brain and other body systems, and this can have an impact for the rest of the child’s life.


It won’t ever be possible to protect our children from every form of stress they may experience and nor should we try, but by avoiding long term toxic stress and being a consistent, calm and present caregiver when they need it, we can limit the impact of this stress response on the brain.

Responsiveness And Attunement

Providing empathetic and consistent responses to your baby’s emotions helps them to feel safe, secure and valued.


Attunement is an important part of the emotional relationship we have with our children. It comes with learning to recognise your child’s individual temperament and needs, this could be recognising when they get hungry or tired, what type of stimulation they respond to and helping them to understand their emotions using mirroring.


Mirroring is where you reflect your child emotions and intensity, use the same tone of voice as them and the same words to show you understand how they feel.  “You wanted the blue bowl but I gave you the red one, that made you sad” 

Relationships are a core part of children’s development, and much of what a child learns comes from the ‘serve and return’ interaction.


So, when your baby cries and you respond with eye contact, sympathetic facial expressions words and a hug you are building neural connections and strengthening the development of social skills.


A study which looked at brain imaging (Romeo at al, 2018) showed that children who had experienced more conversational interaction had greater activation in the Broca’s area of the brain (this area serves a vital role in the generation of articulate speech).



Another study (Kok et al 2015) found that children whose parents promptly and sensitively responded to their child’s signals, had a more secure attachment, larger brain volume and higher levels of cognitive competence.

By being attuned to your baby’s needs and emotions, and responding sensitively and appropriately, you are literally building their brain!

Building The Brain Through Play

Babies’ brains grow and develop through repetition and back and forward interactions.


Play is an essential part of their learning and development, by making regular opportunities for this ‘serve and return’, you will be supporting your baby’s brain to build strong foundations for learning throughout their lives.


How do you do this?

  • Look out for their ‘serve’
  • Give them a ‘return’
  • Name it (you might name the emotion, the person, thing or action)
  • Give them time to respond
  • Note when they are ready to end the interaction


Watch your baby for a cue that they are taking an interest in something. Maybe they are watching a cat walk past them, are they looking excited? Moving their arms and legs? This is an example of a serve, you can return this by acknowledging it and naming it, ‘oh look there’s the cat!, he’s going to have a drink, shall we watch?’. You can then give your little one time to respond and keep the interaction going by taking turns – ‘serve and return’.


Watching for signs your child is ready to move onto something else will enhance your attunement and you will be able to help them to move onto the next activity when they are ready.


Whilst the serve and return interaction is hugely important, it doesn’t mean you need to be a children’s entertainer who is always providing constant activities, rest and free play is also important for brain development.


Free play is play time which is not directed by an adult, it is about letting the child explore and do what feels natural to them at their own pace. You can be present whilst they do this but stay clear of telling them what to do or showing them how the jigsaw fits together, ask them questions for example ‘what do you want to do with the bricks?’ Free play encourages natural curiosity, spatial awareness, confidence and social skills.


Enjoying these free play sessions and following your child’s lead in what they want to do not only allows them to try things for themselves, which is an important part of the learning process, but it makes them feel loved and valued by you.


Research (Bodrova & Leong, 1996) shows that there is a link between play and brain development; children can suffer cognitive underdevelopment if they have no experience in play and it directly influences how the neural circuits of the brain are connected.

So what can we take from all this?

The impact of being empathetic, responsive and playful with our children is quite literally building their brains with the optimal foundations which will support their physical, mental and emotional health for the rest of their lives. Cool hey?!


Shonkoff, J.P., & Phillips, D.A. (Eds). (2000). From Neurons to Neighborhoods: The Science of Early Childhood Development
National Academies’ Press. Retrieved from

Newberger, J. J. (1997). “New Brain Development Research: A Wonderful Window of Opportunity to Build Public Support for Early Childhood Education.” Young Children 52 (4), pp. 4-7.

Tottenham, N., 2018. The fundamental role of early environments to developing an emotionally healthy brain. Policy Insights from the Behavioral and Brain Sciences5(1), pp.98-103.

Romeo, R.R., Leonard, J.A., Robinson, S.T. et al. (2018). Beyond the 30-million-word gap: Children’s conversational exposure is associated with language-related brain function. Psychological Science29(5), 700-710.

Bodrova, E. & Leong, D. J. (1996).  Tools of the mind: The vygotskian approach to early childhood education. New Jersey: Prentice-Hill.

Kok, R., Thijssen, S., Bakermans-Kranenburg, M. et al. (2015). Normal variation in early parental sensitivity predicts child structural brain development. Journal of the American Academy of Child and Adolescent Psychiatry54(10), 824–831.

Gunnar MR, Herrera A, Hostinar CE. Stress and Early Brain Development. In: Tremblay RE, Boivin M, Peters RDeV, eds. Encyclopedia on Early Childhood Development [online]. Published June 2009. .