Understand the core components of early brain development and access downloadable resources to further your understanding about supporting critical periods in brain development.
How can we maximize brain development during the first three years?
Positive early relationships are essential in helping connect those billions of neurons. Optimal child development, including during the perinatal period, relies on children feeling safe, secure, and loved.
Sensitive and responsive adult-child relationships provide a social-emotional environment that helps shape a child’s sense of identity, confidence, and well-being, which in turn shapes their capacity for learning and growth in every aspect.
From the very beginning, the conversations (whether verbal or not) and interactions that you have with children help shape their future as a communicator and member of a community. Sensitive, observant adults can be valuable “thinking partners” to children as they explore, investigate, create, experiment, and build theories of how things and their world work.
What are the “critical periods” in brain development?
Growth in brain volume takes place in the early years of life:
- At 3 months—Brain is more than half of the adult brain volume
- At 1 year old—Brain is about 2 lbs. (.9 kg), nearly ⅔ its adult size
- At 6 years—Brain is almost 3 lbs. (1.4 kg), 95% of its adult size
Size is just one way that a human brain grows. It also grows in connectivity. It is the connection between brain cells that helps children use their brains fully.
Nerve cells, or neurons, play an important role in connecting our bodies and brain together and to the world around us. Our brains have the greatest plasticity at the beginning of life and it decreases as we age. This means that a child’s environment in the early years greatly affects how their brain develops and works.
Scientists have found that some areas of development have time windows that close quickly. These are called critical periods in brain development. Other areas stay open longer and are known as sensitive periods.
- Critical periods in brain development have more distinct windows of time when they start and stop. After the time period ends, the window of opportunity for the skill to develop closes. Sensitive periods start and end slowly. They are the best times for big changes. Change can still happen after these periods, but it takes more effort.
- Sensitive periods are times when the brain is best at learning or improving a specific skill. Many new connections between neurons are formed during sensitive periods, and unneeded ones are eliminated—a process called pruning.
Pruning allows brain circuits to run more efficiently. Early experiences affect the nature and quality of the brain’s developing architecture by determining which circuits are retained and which are pruned through lack of use. In this way, each child’s brain becomes better tuned to meet the challenges of their particular environment.
Overproduction of synapses peaks in early childhood between 5 and 6 years old. Excess synapses are removed by pruning, which peaks in adolescence and continues into adulthood.
Baby Brain Development by Month: What to Expect
Understanding baby brain development by month can help caregivers provide appropriate support. For instance:
- By 6 months, infants typically begin to recognize familiar faces and sounds, indicating progress in memory and recognition skills.
- By 12 months, many babies begin to say simple words. They can also follow basic instructions. This shows their growth in understanding and using language.
- By 24 months, toddlers begin forming two-word sentences and engaging in more complex problem-solving.
Recognizing and Encouraging Cognitive Milestones
By recognizing and supporting key milestones in cognitive development, caregivers help set the stage for lifelong learning and well-being. These early skills—like memory, problem-solving, and attention—emerge in predictable ways, but every child’s journey is unique. Caregivers who are attuned to these stages can better respond to their child’s needs.
Cognitive growth doesn’t happen in a vacuum. It’s fueled by interaction. Eye contact, shared smiles, storytelling, and back-and-forth exchanges all build cognitive skills like language, attention, and memory. Nurturing environments, serve-and-return interactions and secure attachment all contribute to positive cognitive development in babies and toddlers.
Understanding early brain development stages is also important. Early childhood experiences shape brain architecture, emphasizing the importance of responsive caregiving and a supportive environment. Providing the right stimulation at the right time can have a lasting impact on a child’s learning and well-being, helping them build the necessary skills for a bright future.
