The six stages of lifespan development are: infancy, childhood, adolescence, early adulthood, middle age and older age. These reflect the biological, cognitive and psychosocial changes that occur during a person's lifetime, from birth through old age.
The infancy stage, from birth to two years, is characterized by the neurons making increasingly dense connections, continual bonding with parents, learning the concept of object permanence, and developing the basic structure of language. The childhood stage takes place from two to 10 years. Children are becoming more independent in this phase, with increased memory, analytical skills and a higher need for peer significance. In the adolescence phase, from 10 to 20 years, thoughts are more abstract, scientific and idealistic. Sexual orientation develops, and self-identity and the influence of peer pressure increases.
Early adulthood is from 20 to 40 years old, and practical thought dominates the intellect at this point. A need for achievement and affiliation are also prominent in early adults. Middle age is from 40 to 65 years old, and it brings greater cognitive awareness and stabilization of personality traits. Ages 65 years and up is the older age stage. In this stage, people suffer short-term memory loss, but they also show an increase in semantic-based knowledge. There is also a subjective feeling of well-being that is greater than at any other stage of life.