Chapter Four: Brain Development from Conception to Age 8

The human brain is the most unique thing about each of us. It is home to our memories and our plans; we use it also for essential activities such as breathing and regulating our heartbeat, but we can also use it for making up bad jokes and excuses. Our brains help define who we are as individuals as our biology interacts with our environments.

During the first eight years of life, the brain of a child is doing an enormous amount of work, day and night. In this chapter, we will explore the typical development of the human brain, starting at conception. To understand this development, we will need to delve into the inner workings of the brain, from the smallest parts of the neuron all the way up the four lobes of the cerebral cortex, where so much of our daily experience takes place.

The brain plays an important role in all aspects of early development, and the experiences that happen early in life lay the foundation for how the brain will operate across the lifespan. For that reason, it is essential for anyone who is planning to work with infants, toddlers, and young children to understand the earliest stages and milestones of brain development. Ensuring that children’s brains get high quality input right from the start is the best way to ensure a lifetime of brain functionality.

Earlier, we talked about the four domains of development: physical, cognitive, social, and emotional. The brain develops in each of these domains, just as every other part of the child does. Typically, the brain is most closely associated with cognitive development. Cognition, after all, is largely about brain functions such as memory, attention, processing speeds, and intelligence. When we talk about people who are smart, we often refer to them as having a “big brain” or being a “brainiac.” As will be discussed through this book, one of the most impressive cognitive feats of the brain is the development of spoken (and later written) language.

But our brains also develop – and help guide development – in the other three domains as well. One of the primary functions of the somatosensory cortex of the brain is to accept, integrate, and act upon sensory information in the form of physical sensation. This narrow strip of the cerebral cortex is essential in nearly everything we do each day, helping us to know when we are touching objects, which in turn informs the systems that maintain our balance and orientation in space. These parts of the brain are necessary for learning to stand, walk, run, jump, and maybe even surf! Without the brain’s constant integration of important sensory information, our physical development would be significantly delayed (Jensen, 2019).