Why Investments in the First Five Years Work Best


Human Brain Development and Early Childhood


“For brain development, 3 is like pushing middle age.”

Dr. Jack Shonkoff, Center on the Developing Child, Harvard University


  • Early experiences, especially during the first five years of life, affect the development of brain architecture, which provides the foundation for all future learning, behavior, and health. Just as a weak foundation compromises the quality and strength of a house, adverse experiences early in life can impair brain architecture, with negative effects lasting into adulthood.


  • Brains are built over time, from the bottom up. The basic architecture of the brain is constructed through an ongoing process that begins before birth and continues into adulthood. Simpler neural connections and skills form first, followed by more complex circuits and skills. In the first few years of life, 700 to 1,000 new neural connections form every second. After this period of rapid proliferation, connections are reduced through a process called pruning, which allows brain circuits to become more efficient.  Early experiences affect the nature and quality of the brain’s developing architecture by determining which circuits are reinforced and which are pruned through lack of use. Some people refer to this as “use it or lose it.”


  • It is easier and less costly to form strong brain circuits during the early years than it is to intervene or "fix" them later. Brains never stop developing—it is never too late to build new neural circuits—but in establishing a strong foundation for brain architecture, earlier is better.


  • Exposure to positive experiences and nurturing environments during early childhood builds a strong neural foundation for more complex learning and behavior later in life.  Environmental stress, including lacking one loving and consistent caregiver, affects a child's cognitive, linguistic, social, emotional, and motor development. Moreover, the frequency and quality of words spoken to a child significantly affects I.Q., literacy, and academic success later in life.


Additional Resources:

Harvard University Center on the Developing Child

The Science of Early Childhood Development (Harvard) 

30 Million Word Gap 

From Neurons to Neighborhoods

Meaningful Differences in the Everyday Experiences of Young American Children