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.
Early childhood is a stage in human development. It generally includes toddlerhood and some time afterwards. Play age is an unspecific designation approximately within the scope of early childhood. Some age-related development periods and examples of defined intervals are: newborn (ages 0–5 weeks); infant (ages 5 weeks – 1 year); toddler (ages 1–3 years); preschooler (ages 3–5 years); school-aged child (ages 6–11); adolescent (ages 12–17).
