Contrary to popular belief, the structure of our brains as they develop in early childhood is determined by more than just our genes. The experiences we have in the first years of our lives also affect the physical architecture of the developing brain.

That has consequences for our health and for our communities—because the brains we take with us into adulthood determine our physical and mental health, our ability to maintain healthy relationships, and our ability to contribute as productive, responsible citizens.

Because brains are built in stages, with more complex structures built on simpler structures, it’s crucial to get the early years right. Think of building a house: before framing the walls, a foundation has to be poured. Before wiring the house, walls and floors need to be built. Our brains are also built in sequence, and early childhood is about laying a solid foundation to serve as a base for later development. Once architecture is built, foundation repairs are costly, so supporting early childhood is a worthwhile investment. 


Kids can’t build strong brains by themselves—they need positive, nurturing interactions with trusted caregivers to support their development. These positive interactions are the bricks that build sturdy brain architecture, leading to improved learning and behaviour as well as better physical and mental health throughout life. To learn about what kind of interactions build strong brain architecture, read about serve and return

The Science of Brain Architecture

Brain development is a process that begins shortly after conception and continues into our mid-20s. The brain is formed from an embryonic structure called the neural tube in a process called neurulation. Over the course of the next few months, these embryonic brain cells proliferate, differentiate into specific cell types, and migrate to take up appropriate positions within the growing structure of the brain. Once there, these cells begin to form the connections that will make up the brain’s neural circuits.

The first few years of life are a period of intense activity in the developing brain: connections are rapidly being formed among brain cells that allow them to exchange information and form circuits. These circuits form the architecture of the brain and are what allow us to interpret information from our environment and interact with the world around us: every thought, feeling, and action we perform originates from our brains. The most basic circuits that govern our most basic skills, like our sensory systems, form first and provide the foundation and scaffolding for more complex circuits governing more complex behaviours, like language, attention, and emotional regulation, to build on top. The circuits governing all of our skills are built sequentially, with simpler skills providing the support for more complex behaviours over time. In fact, our most complex skill set, called executive function, doesn’t finish developing until we are in our mid-twenties.


Once the connections in a given brain circuit are formed, the brain refines these connections through experience: the connections that get used the most become very strong and resistant to change, and those that get used the least get weaker and are eventually lost. This is a normal developmental process called pruning, and it allows the brain to create more efficient circuits over time. What’s important to remember is that the experiences we have in childhood will have an impact on how our brain’s circuits get used: high-quality experiences will reinforce important cognitive, social, and emotional skills that are necessary for learning, forming close relationships, and positive health outcomes, and will create a solid foundation for additional development. Children who do not have these same opportunities, or who are exposed to negative experiences like maltreatment or witnessing domestic violence, often have poorer outcomes in comparison. In this way, the quality of the brain’s architecture can have a profound influence on our outcomes throughout life.

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