Fun fact: All babies are born with billions of neurons bumping around their brains…BUT very few of those neurons are actually connected. It’s like each one is trying to play telephone, but very few are picking up! That’s where you come in. You’re the operator. It’s up to you (and other loved ones and caregivers) to help make sure signals get sent through the brain and make connections. How do you help do that? You offer your little one lots of repeated positive experiences. Research has shown that doing this—especially from birth to age 3—creates neural pathways that ready your child to absorb new information, new environments…and even love! Here, learn more about how your child’s amazing brain grows and develops in their earliest years—and how you can help.

Your Baby’s Brain: Primed for Growth!

While brand new babies may look like little helpless blobs who offer little more than cries and sighs, the truth is, their rapidly developing brains are working overtime, gearing up to eventually be able to giggle, talk, walk, run, draw, kick a ball, and more. In fact, your child’s brain creates more than 1 million fresh neural connections (synapses) every second of their first few years of life—more than at any other time in life! This means that your bub’s brain is most flexible and most primed to learn during their earliest years. More fascinating brain facts:

  • A newborn has all the brain cells they’ll ever have.

  • Your child’s brain doubles in size in the first year!

  • Children’s brains continue to grow to about 80% of adult size by age 3.

  • At age 2 or 3, the brain has up to twice as many synapses as it will have in adulthood.

  • After age 3, these brain connections slowly began to be reduced through a process called pruning. This helps little one’s brain circuits become more efficient.

  • By age 5, a child’s brain is 90% finished growing.

Your Baby’s Brain: Nature Versus Nurture

Your baby’s early brain development is strongly affected by genetics. Their genes form neurons and, essentially, take care of the basic brain wiring. But genes don’t finish the job! Instead, your baby’s brain adjusts, adapts, and fine-tunes itself based on the info received from their environment. All the input your bub receives from you and their surroundings stimulates neural activity. For example, the more you talk, read out loud, and sing, the more your baby hears, which means the more synapses get activated in those brain regions. All the repetition creates stronger synapses. And on the flip side, synapses that are rarely used wind up getting weaker…and they’re super vulnerable to getting pruned out!

What Your Baby’s Developing Brain Needs

A child’s budding brain grows and learns best in a safe environment, free of neglect and extreme or chronic stress. Also imperative: responsive caregivers, oodles of playtime, and good nutrition. Here are some of the most important things you can do to help build your baby’s brain from birth to age 3.

Responsive, Loving Parenting

According to Zero to Three, America’s leading early childhood development nonprofit, emotionally nourishing relationships during baby’s first three years lay the foundation for lifelong health and well-being, dramatically influencing brain development, social-emotional, and cognitive skills. So, what makes a parent-child connection nourishing? For one, it’s about understanding your little one’s needs—and then responding appropriately. Doing this not only nourishes your baby’s brain, it helps to protect their brains from stress, according to the Centers for Disease Control and Prevention. While reading a baby’s mind—and always providing exactly what they need immediately is, well, daunting, rest assured: A 2019 study in the journal Child Development found that accurately responding to your baby’s needs about half the time still works wonders at building bonds with your baby. “Babies are very forgiving,” noted researchers. “You don’t have to be perfect, you just have to be good enough.”

If you’re ever in doubt as to how to respond to your upset little one in their first months of life, ask yourself: Is my baby hungry? Is my baby uncomfortable? If the answer to either is yes, you know what to do. If the answer is no, turn to Dr. Harvey Karp’s groundbreaking 5 S’s for soothing babies. Swaddling, shushing (white noise), swinging, sucking, and holding your baby in the side/stomach position all work to activate Baby’s natural calming reflex, which is their internal “off switch” for fussiness and “on switch” for sleep.

Good Nutrition

Another important aspect to a baby’s brain growth: The quality of their nutrition. For instance, infants and small children who don’t get the right number of calories and protein don’t grow adequately—physically or mentally. When compared to well-fed little ones, malnourished baby’s brains are literally smaller and, as a result, many suffer lasting behavioral and cognitive deficits, including slower language and fine motor development. Some key ways to ensure your bub’s diet fosters optimal brain development include…

  • Breastfeed if you can. Breastmilk is uniquely designed to continuously change throughout lactation to always meet your baby’s growth and development needs. Plus, research shows that breastmilk specifically helps neurodevelopment of both term and preterm babies.

  • Offer iron. Most newborns have enough iron stored in their wee bodies to last them about 6 months. After that, breastfed babies need an external source of iron. The reason? Iron deficiency has been clearly linked to cognitive deficits in young children. Iron helps oxygen travel in the red blood cells and for healthy brain development.

  • Serve whole milk. Baby’s brain cells are sheathed in a special membrane called myelin that helps cell-to-cell communication…and this stuff grows a lot in their early years! You know what facilitates that rapid growth? Fat! That’s why about 50% of a 0 to 2-year-old’s diet needs to be fat. Breastmilk or formula does the trick for year 1 (wait to introduce cow’s milk until after your child’s first birthday), then whole cow’s milk offers up plenty of fat and protein till age 2. (More on healthy fats to add to your baby’s diet.)

  • Serve a healthy variety. Once your child is consuming solids, you want to provide a variety of nutritious foods to hit all the nutrient bases. That means a healthy mix of proteins (including fish), whole grains, fruits, and veggies. (Learn more about brain-boosting foods for toddlers.)


Play is essential for baby and big kid’s brain development. Through play, little ones explore their environment, test how things work, practice skills, and make decisions—all of which help to strengthen and expand your bub’s brain circuits. Serve-and-return interactions make up a big part of this brain-building play—for example, when your sweet pea coos and you coo back. Or when you flash a big smile at your baby, and your baby sends one right back to you. This back-and-forth dance (which progresses to peek-a-boo and pat-a-cake) helps shape the architecture of your little one’s developing brain, and it acts as a buffer to stress, which protects your little one’s brain development from disruption. (Learn more about the stages of play and how play bolsters babies’ brains.)


Sometimes, reading to a tiny baby who has zero clues what you’re talking about seems pointless. It’s not! Every time your little one hears you read, they add to a rich network of words in their brain, which provides the building blocks for language—and it boosts parent-child bonding. Plus, research shows that the quality and quantity of read-aloud in early infancy and toddlerhood can predict a child’s vocabulary up to four years later…that means prior to school entry. Think about it like this: When you read to your little one…

  • Your baby learns about different emotions and expressive sounds, which supports their budding social and emotional development.

  • You often point to words and picture—and ask questions (“Where’s the puppy?”), which buoys a baby’s thinking skills and social development.

  • Your baby tries to copy-cat your sounds, they learn words, and start to recognize pictures…all of which improves language skills.

When reading to the youngest bunch, grab books that feature faces, bright colors, and different patterns. For baby’s between 4 months and 6 months, do more of the same—and look for reads with repetitive or rhyming text. (Learn how to make the most of your storytime, plus great brain-building books to consider for your little library.) 


While it may not always seem like it, infants spend most of their first year sleeping! All those ZZZs are needed to help your baby’s brain grow. After all, neural connections and sensory memories come together during sleep! In the first three to four months, the 5 S’s continue to activate your baby’s calming reflex to quiet fussing and bring on sleep. Beyond that, set a consistent, predictable, and comforting bedtime routine for your little one. Establishing positive sleep practices during Baby’s first years sets the stage for good sleep—and proper brain development. For example, a study in the Journal of Epidemiology and Community Health found that inconsistent bedtimes throughout early childhood—but especially at age 3—may result in lower reading, math, and spatial awareness scores by age 7. 

Final Thoughts on Baby’s Brain Development

While so much of your little one’s brain develops during their first three years, that does not mean that all that exciting progress grinds to a halt once they blow out their third birthday candles! In fact, brain regions that involve social, emotional, and cognitive abilities continue to develop well into the teen and early adult years. So, keep doing—and adapting—all the above! At the same time, know that children who have experienced extreme stress or neglect in infancy and early childhood are not doomed. While these precious children are at greater risk for adverse effects on brain development, establishing reliable, safe, and nurturing relationships (and appropriate treatment when needed) can substantially help little ones who were not given the ideal start.

More ways to bolster baby’s brain development



  • Zero to Three: Why 0-3?
  • Harvard University, Center on the Developing Child: What Is Early Childhood Development? A Guide to the Science
  • First Thing’s First: Brain Development
  • The Urban Child Institute: Baby’s Brain Begins Now: Conception to Age 3
  • Harvard University, Center on the Developing Child: InBrief: The Science of Early Childhood Development
  • Centers for Disease Control and Prevention (CDC): Early Brain Development and Health
  • Secure Base Provision: A New Approach to Examining Links Between Maternal Caregiving and Infant Attachment, Child Development, February 2019
  • Science Daily: ‘Good enough’ parenting is good enough, study finds
  • Zero to Three: How does nutrition affect the developing brain?
  • Human Milk and Brain Development in Infants, Reproductive Medicine, June 2021
  • CDC: Iron
  • University of Georgia Extension: The Importance of Play in Baby's Brain Development
  • UNICEF: Building babies’ brains through play: Mini Parenting Master Class
  • Harvard University, Center on the Developing Child: Three Core Concepts in Early Development
  • Vanderbilt University‘s Peabody College of Education and Human Development, Prenatal-to-3 Policy Impact Center: Why Do We Focus on the Prenatal-to-3 Age Period?: Understanding the Importance of the Earliest Years
  • Cleveland Clinic: The Benefits of Reading to Babies
  • AAP News: Reading with children starting in infancy gives lasting literacy boost
  • Nemours, KidsHealth: Reading Books to Babies
  • Sleep and Early Brain Development, Annals of Nutrition and Metabolism, June 2020
  • Time for bed: associations with cognitive performance in 7-year-old children: a longitudinal population-based study, Journal of Epidemiology and Community Health, 2013
  • Harvard University, Center on the Developing Child: 8 Things to Remember about Child Development

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Disclaimer: The information on our site is NOT medical advice for any specific person or condition. It is only meant as general information. If you have any medical questions and concerns about your child or yourself, please contact your health provider.