Child development refers to the processes a human child must undergo in order to move from being a dependent baby, to an independent adult. These processes are physical, psychological, emotional and biological.
The most obvious aspect of child development is the physical growth a child goes through during the first two decades of his life. When an infant is born, he cannot even hold his head up independently. Within the first year, the child learns to support his head, sit up, crawl and usually walk. Additional physical changes occur throughout childhood, including growing larger, but also changes in physical makeup, such as the widening of the hips in adolescent girls.
Child development also involves the maturation of cognitive abilities and emotional intelligence. Children go from being mostly self-centered and dependent to developing a sense of empathy and a realization of where they fit in with the larger society around them. They also learn to control their emotions in healthy ways, and interact within society for the purpose of survival and companionship. For instance, a toddler may have thrown tantrums when emotions become overwhelming, while an older child or adult may have learned to talk through his feelings as a healthier alternative.