Human life is the succession of different stages in our development. Every 10-15 years, we change physically and emotionally. The first 10 years of human life are the time of the most rapid development of a human. The infant visibly grows with every month, and by the age of three kids look quite developed. The same three years is nothing for a thirtyish person in the midst of their productive age. On the other hand, septuagenarians age fast, and every 5 years change them visibly. Wonderful transformations happen to the humans during their life, most vivid in the first and the last decades of life.
The period we typically call childhood is divided into several stages of development. Scientists define no less than 3 or 4 stages of the childhood – they are infancy, early childhood, childhood itself (the middle one), and late childhood. Infancy is the period from birth to the 18 month of life. The baby gradually takes control over its body, it learns to crawl, sit, and stand. Mental changes allow infants to recognize parents and their voices. The infant completely depends on the care of their parents, for much of these 18 months, the mother can breastfeed.
Early childhood lasts from the 18 month up to the age of 3. The child learns to walk, talk, and use the toilet independently. It interacts with other children and becomes social. The middle childhood is the period since the age of 3 to 6. It is the age of active socialization when the child learns to interact with a group. Late childhood is the period when the child is 6 to 10 years old. The child develops fast mentally and emotionally and prepares for sexual maturing.
Adolescence is an introduction into adulthood. Teens are more adult-like physically, but their emotional and mental development cannot catch up with the physical growth. Yet even early adulthood is the time of active exploration and learning.