Milestones of the maturing brain
The BRAIN magazine
Image: Filip Mroz/Unsplash
Photo by Filip Mroz on Unsplash
Brain development is very different to the development of other organs. At birth, the heart, lungs and kidneys are fully developed. The new born brain, however, is not.
At birth, a baby has only rudimentary sensory, motor and cognitive capacities. Without care, attention and the protection of its caregivers, the baby could not survive.
The reason the brain is underdeveloped at birth is precisely the reason it is so incredible: it must learn from and adapt to its experiences of the world.
While still in the womb – cocooned in safety, conveniently fed by its mother, and with only limited scope for sensory input – a human baby is not exposed to the world, and its brain does not have a large role to play in movement, learning, or processing of sensory information.
After birth, we need to make sense of the world, interact with objects and people, plan actions and predict their consequences, learn from our successes and failures, and store experiences away for future reference: this takes time.
To make sense of all this new information, the brain makes new and refines existing synaptic connections between neurons throughout childhood and adolescence, in the process, gradually expanding our cognitive capacities.
Leaps and bounds of the developing brain
During the first two years of life, the brain experiences remarkable growth as babies become more independent. Many changes occur in the brain, and a baby hits many new developmental milestones. For example, perceiving something they were not capable of perceiving before or learning to do new things seemingly overnight.
With the first milestones, babies begin to sense their surrounding world as their five senses develop.
As vision improves, they can now perceive their carers’ facial expressions and develop a ‘social smile’ - an intentional gesture of warmth.
At about six months, reflex responses start to make way for a growing awareness of the outside world and increasing control
During the first two years of life, the brain experiences remarkable growth as babies become more independent. Many changes occur in the brain, and a baby hits many new developmental milestones.
For example, perceiving something they were not capable of perceiving before or learning to do new things seemingly overnight. With the first milestones, babies begin to sense their surrounding world as their five senses develop. As vision improves, they can now perceive their carers’ facial expressions and develop a ‘social smile’ - an intentional gesture of warmth.
At about six months, reflex responses start to make way for a growing awareness of the outside world and increasing control over their own bodies. They can now crawl, sit upright, and easily manipulate objects with their hands (and get them to their mouths). They also begin to respond to their own name and understand short sentences like “it’s time to eat” or “we are going out.”
The reason the brain is underdeveloped at birth is precisely what makes it so incredible: it must learn and adapt to its experiences of the world.
Between six and 12 months, development of those parts of the brain that control social and emotional skills accelerates, making this period an important stage for forming bonds with caregivers. Similarly, elevated activity in regions involved in memory and language allows babies to rapidly learn new words.
Continuously increasing levels of myelination – an insulating layer that covers neurons and axons in the central nervous system and speeds up nerve signal transmission – allows increasingly well-coordinated movements so that by 12-18 months, most babies take their first steps.
Unfortunately, tantrums and frustrations also commonly happen at this age, as the developing pre-toddler brain still lacks control of feelings and emotions that also cannot be well-communicated because of its still limited language abilities.
Image: Senjuti Kundu/Unsplash
Photo by Senjuti Kundu on Unsplash
Milestones in brain development
1 month
At one month, the visual system is developing, and babies can start to focus beyond 20-30 cm. Babies begin to be interested in the world around them and will smile for the first time.
2 months
Automatic reflexes like jerking when the head moves back have faded by now. A baby has the motor development to find and clutch their hands. They can recognise familiar faces.
4 months
Babbling begins. A baby will mimic facial expressions and communicate hunger or tiredness with crying. They may begin to roll.
6 months
Responds to their name. Bring things to their mouth. Begins to sit without support.
9 months
Starts pointing. Copies sounds and gestures. Loves peek-a-boo. Can grasp small items with fingers. Pulls up to
stand. Begins crawling. Understands object permanence (knows a hidden object is still there).
12 months
Responds to simple directions. Can use basic body language like shaking head for ‘No.’ Can put things into containers. Can drink from a cup. Starts to walk.
18 months
Branches out to explore with a caregiver close by. Can say some basic words. Can start to pretend play. May have tantrums.
2 years
Copies other adults and children. Shows defiant behaviour (showing their own mind). Can use basic 2-4- word sentences. Easily find hidden things. Can sort shapes and colours. Can use blocks to build. Names items like ‘cat’ or ‘ball’ in books. Can kick a ball and run.
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