According to the Child Welfare Information Gateway, when a child is born she has nearly all of the neurons she’ll ever have. A newborn’s brain has a well-developed brainstem and midbrain, which enable the newborn to carry out the bodily functions necessary for life. But the sections of the brain that are involved in regulating emotions, language, and abstract thought grow and develop after birth. Brain development--in other words, learning--is the process of creating, strengthening, and discarding connections, or synapses, among brain neurons.

Rapid Development of Synapses, or Connections Between Neurons

The synapses a child is born with govern functions like a child’s heart rate and breathing, eating and sleeping. However, during the child’s early years, synapse development in response to the child’s experiences is fantastically fast; according to the Child Welfare Information Gateway. At its peak rate, “the cerebral cortex of a healthy toddler may create 2 million synapses per second.” By age 3, your child’s brain has reached nearly 90 percent of its adult size; the growth in each part of the brain depends in a majority on receiving stimulation. As noted by the Gateway, this stimulation provides the foundation for learning.

Development of Myelination, or Insulation of Mature Brain Cells

Myelin is tissue that insulates brain cells with a sheath that ensures clear transmission across synapses; the reason young children process information slowly is because their brain cells lack myelin needed for quicker transmission of nerve impulses. According to research cited by the Child Welfare Information Gateway, a child’s experiences affect the rate and growth of myelination all the way through young adulthood.

Newborns and Infants

According to the Centers for Disease Control and Prevention, newborns and infants are beginning to recognize voices, focus their eyes, and develop bonds of love and trust 1. This will be the foundation of the learning process of memory, language, thinking and reasoning. At this stage your child is like a sponge in the way he will absorb and be impacted by his experiences, so the way you hold, cuddle, and interact with the child will set the basis for how he interacts with you and others in coming years.

Warnings for Newborns and Infants

Though his brain is growing fast, your newborn will still have weak neck muscles; always support his head and avoid situations that could shake him.


As a toddler, a child becomes mobile. With this will come independence and defiance. Be strong and be an all-star parent, and provide your child with balanced support and encouragement during this phase in spite of the personal challenges your patience may face; research cited by the Department of Health and Human Services has shown that both intensive and prolonged stress can disrupt early brain development and compromise the functioning of her nervous and/or immune system. Specifically, experiencing unhealthy stress when young can affect the development of your child’s stress circuits, causing the child to develop a low stress threshold and become overly reactive to adverse experiences throughout life.