Early Brain Development

The actual physical structure of the brain changes based on the environment. This means that what you do with your baby or toddler results in physical changes in your child’s brain1,2. Environmental enrichment causes changes at the neuronal level and results in improvements in cognitive performances1. The important effect of the environment on brain development is evident from a study that shows a family’s socioeconomic status predicts statistically significant differences in both brain structures and functions2.

Educating parents about the importance of the environment can also have long-term positive impacts on the lives of at-risk infants. For example, in weekly one-hour sessions over two years, Jamaican health workers encouraged parents to play and interact with their babies in a way that would help their cognitive abilities. Twenty years later, the children who were involved in the intervention made 42% more in their jobs than a control group that did not receive the early intervention3.

Why does the early environment have such a large impact on the physical structure of a child’s brain?

  • Because about 75% of brain mass is formed by age two
  • Since infants and toddlers have thousands of new synapses forming in their brains every second
  • Younger infants have more neuroplasticity than older toddlers (neuroplasticity is the ability of the brain to change based on environmental input)

We strongly encourage parents to use the tips on this website to create a positive, language-rich environment for infants and toddlers. In addition, it is imperative to provide adequate nutrition for proper brain development both during pregnancy and during infancy4, 5.

Edelman’s Theory of Neuronal Group Selection6 states that there are more elaborate connections in the brain when multisensory learning occurs compared to learning through one sensory system. This multisensory information is matched in time. In other words, to be multisensory information, the baby would need to receive the information at the same time. For example, a baby smelling a flower while looking at the flower is learning through at least two sensory systems.

According to this theory, movement information is used along with sensory information for infants and movement could be considered as a sense for infants. If a baby learns through three senses (for example, visual, auditory, and haptic) along with movement, then there would be an elaborate series of brain connections that form from the:

  • visual cortex to the auditory cortex,
  • auditory cortex to the somatosensory cortex (for the haptic/touch information),
  • auditory cortex to the motor cortex (for the movement information),
  • visual cortex to the somatosensory cortex,
  • visual cortex to the motor cortex, and
  • somatosensory cortex to the motor cortex.

You can see from the above that there are many more brain connections that are forming when there are three senses along with movement compared to learning through a single sensory system, according to Edelman’s Theory of Neuronal Group Selection. Having a more elaborate series of connections allows multiple ways for infants to access this information. The actual physical structure of the child’s brain changes based on the number of sensory systems that are incorporated.

About 75% of the mass of the brain is developed by age 2 and 90% by age 5.Infants have more neuroplasticity than 3-year-olds and a 3-year-old has more neuroplasticity than a 5-year-old. This means it is easier to make changes in younger infants’ brains than it is in older children’s brains.

Since about 90% of brain development occurs by age 5, what the child is taught in the first years of life has a lasting impact on the child. Furthermore, the best predictor of academic success at the end of high school is how well the child was doing on the very first day of school7. Negative caregiving has long-term negative effects on brain development including working memory and inhibitory control functions8.



1 Sale, A., Berardi, N., & Maffei, L. (2009). Enrich the environment to empower the brain. Trends in Neuroscience, 32(4):233-9.

2 Brito, N. H., & Noble, K. G. (2014). Socioeconomic status and structural brain development. Frontiers in Neuroscience, 8, 276. http://doi.org/10.3389/fnins.2014.00276

3 Gertler, P., Heckman, J., Pinto, R., Zanolini, A., Vermeersch, C., Walker, S., Chang, S., & Grantham-McGregor, S. (2014). Labor market returns to an early childhood stimulation intervention in Jamaica. Science, 344 (6187), 998-1001.

4 Morgane, P., Austin-LaFrance, R., Bronzino, J., Tonkiss, J., Diaz-Cintra, S., Cintra, L., Kempers, T., & Galler, J. (1993). Prenatal malnutrition and development of the brain. Neuroscience & Biobehavioral Reviews, 17(1), 91-128.

5 Tam, E. W. Y., Chau, V., Barkovich, A. J., Ferriero, D. M., Miller, S. P., Rogers, E. E., … Innis, S. M. (2016). Early postnatal docosahexaenoic acid levels and improved preterm brain development. Pediatric Research, 79(5), 723–730. http://doi.org/10.1038/pr.2016.11

6 Edelman, G. M. (1987). Neural Darwinism. New York: Basic Books.

7 Duncan, G. J., Dowsett, C. J., Claessens, A., Magnuson, K., Huston, A. C., Klebanov, P., et al. (2007). School readiness and later achievement. Developmental Psychology, 43, 1428–1446.

8 Cuevas, K., Deater-Deckard, K., Kim-Spoon, J., Watson, A. J., Morasch, K. C. and Bell, M. A. (2014). What’s mom got to do with it? Contributions of maternal executive function and caregiving to the development of executive function across early childhood. Dev Sci, 17: 224–238. doi:10.1111/desc.12073