Compared to infancy, body size increases more slowly during early childhood, and the child's shape becomes more streamlined. The brain continues to grow faster than other parts of the body. The cortex, especially, shows gains in myelinization and formation of synapses, followed by synaptic pruning.
Hand preference strengthens, a sign of greater brain lateralization.
In addition, connections between different parts of the brain increase. These changes support improvements in a wide variety of physical and cognitive skills. Factors affecting physical growth and health in infancy and toddlerhood continue to be influential in early childhood. Heredity affects physical growth by regulating the production of hormones. Extreme emotional deprivation can interfere with the production of growth hormone, thereby stunting children's growth.