Your Child’s Brain Development: 3 to 5 Years

If it seems like every time you turn around, your child has learned a new skill; you’re not mistaken. The preschool years are a period of extremely rapid brain development, fed by two simultaneous processes: synaptogenesis and myelination. Synaptogenesis links neurons together into sophisticated networks through the creation of new synapses in the brain. Meanwhile, myelination sheathes the nerves in a fatty, protective coating that enables faster transmission of brain signals. The elaborate, increasingly efficient network that results allows for speedy communication between various regions of the brain and leaves your child poised to learn anything and everything, from a new word to a new song to a new concept about how the universe works. Here are some of the ways you may see brain development displayed in your child right now.


Children’s brains grow in a preprogrammed, bottom-to-top sequence, from the brainstem, which controls the most basic bodily functions, to the cortex, which governs the most complex thinking. Experts agree that there are critical periods in brain development during which young children are especially sensitive to the environment (which includes everything from getting the proper stimulation to getting the proper nutrition) for learning. From there, cognitive advancements are a matter of stimulating the neurons and their connections, which strengthens them and broadens their functionality.

While most children aren’t reading by the age of 5, between 3 and 5, they are learning to recognize letters and associate them with sounds. Showing your child the ABCs while saying the letters aloud requires them to use at least three different areas of the cortex to process that information. Specifically, the visual cortex sorts out the symbols your child’s eye sees, an area called the angular gyrus associates those symbols with the sounds of the letters, and Wernicke’s area is where the connection to understanding is made.


As your child grows more agile—running, jumping, climbing, and learning to perform ever more complicated feats—their brain continues to hone the processes that are key to balance and coordination. During the preschool years, they are also developing executive functions, which control memory, timing, and sequencing—these abilities are essential for more complex physical activities, such as riding a bike and throwing and catching a ball. Repetition is key to advancement; neural connections are strengthened with the use of both large- and small-muscle movements. You’ll see the progress when your child practices activities like walking backwards, skipping and hopping on one foot.

At this age, fine motor skills also become more important, as your child learns to write, draw, build, and create in ways that require their hands to do exactly what their brain tells them to.


Ever wonder why it’s difficult to distinguish and understand sounds and syllables that aren’t used in your native language? Your child’s brain first forms the synaptic connections necessary to hear and produce all the sounds used by all languages around the world. But with use and disuse, these connections either become strengthened or are pruned away to favour those they hear and use in their native language.

As time goes on, you’ll see a change in your child’s ability to distinguish between the language, or languages, spoken around them and those that are unfamiliar. In infancy, a baby reacts to all spoken language, and by the preschool years, a child is engaged when they understand what’s being spoken, but they may ignore or appear confused by foreign tongues.

Your child’s communication skills take a quantum leap during these years. They become much better listeners and respond more readily when spoken to. It’s not just that their sentences are getting longer and more complex; they can follow directions with more than one step, for example, and they can describe a sequence of events in relative order. They have even beginning to think out loud and talk through situations and feelings.


The “use it or lose it” rule of brain development is key in understanding your pre-schooler’s socialization. Studies have shown dramatic differences between children who experience frequent interactions with parents and other caregivers and children who are raised with less stimulation. Up to the age of 3, your child’s brain produced an excess of synaptic connections—many more than they will ultimately need. Social interactions reinforce the synaptic connections involved with language and other forms of communication and social expression, while those not used to become weak and disappear with disuse. In this way, your child’s social environment literally shapes their brain, a process known as plasticity.

You will see similar changes in other areas of social interaction, particularly as your child begins to establish relationships with their peers. Between ages 3 and 5, fuelled by the development of the cerebral cortex, your child goes from believing that everyone sees the world the same way to understanding that there can be multiple points of view. In fact, by about age 4, your child is well aware that what they want to play with now (that toy train) may be in direct conflict with what another child wants (those balls). Much of this learning and understanding takes place through play, which experts stress is a complex series of skills that take time to develop. As your child begins to play with others, they will learn via trial and error to cooperate and negotiate with other children through sharing and taking turns.


  1. Zero to Three on brain development.
  3. “Caring for Your Baby and Young Child, Birth to Age 5 (5th Ed)” by the American Academy of Pediatrics.
  4. Health and Human Services, Understanding the Effects of Maltreatment on Brain Development - How the Brain Develops. Available at:
  6. “The Wonder Years: Helping Your Baby and Young Child Successfully Negotiate the Major Developmental Milestones” by American Academy of Pediatrics (2006).
  7. “Effects of physical activity on children’s executive function: Contributions of experimental research on aerobic exercise” by John R. Best, Developmental Review (2010).
  8. “Normal Development of Brain Circuits Neuropsychopharmacology” by Gregory Z Tau and Bradley S Peterson, Neuropsychopharmacology (2010).
  9. Zero to Three: Play. Available at: