A large amount of research has been done on the effects of sleep and brain development in the history of mankind, however, there have been substantial leaps of late. The effects of poor sleep in infants later in life have been touched on, however, there is still a lot that needs to be determined because these studies are longitudinal. What we do know for sure is that the early years in life, especially the first 3 are exceptionally important in the development of a Childs' brain. Everything he or she sees, touches, smells, and/or hears helps to shape the brain for thinking, feeling, moving, and learning. In these first 3 years of life, the brain undergoes an amazing period of development where more than 1,000,000 million neural connections are formed each second.

Babies have large heads to accommodate their rapidly growing brains. At age 2, the brain is already 80% of the size of an adults' brain. Brain development happens in stages, with different parts of it growing and developing at different points in time. Something to take into consideration is that most of the brain cells are formed before birth, however, most of the connections or synapses in the brain are formed in infancy and early childhood. This brain development allows the child to then crawl, eat, sleep, walk, and talk, etc.