Childhood is the age span ranging from birth to adolescence. According to Piaget's theory of cognitive development, childhood consists of two stages: preoperational stage and concrete operational stage. In developmental psychology, childhood is divided up into the developmental stages of toddlerhood (learning to walk), early childhood (play age), middle childhood (school age), and adolescence (puberty through post-puberty). Various childhood factors could affect a person's attitude formation.
Living organisms including humans are social when they live collectively in interacting populations, whether they are aware of it, and whether the interaction is voluntary or involuntary.
Youth is the time of life when one is young, and often means the time between childhood and adulthood (maturity). It is also defined as "the appearance, freshness, vigor, spirit, etc., characteristic of one who is young". Its definitions of a specific age range varies, as youth is not defined chronologically as a stage that can be tied to specific age ranges; nor can its end point be linked to specific activities, such as taking unpaid work or having sexual relations without consent.
As I approve of a youth that has something of the old man in him, so I am no less pleased with an old man that has something of the youth. He that follows this rule may be old in body, but can never be so in mind.
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