Lifespan is the term used to define the period from conception through to the end of life. The study of human development across the lifespan reveals patterns of growth, change, and stability. The lifespan is divided into a series of developmental periods, each associated with the appearance of distinct characteristics relating to physical, cognitive, social, and emotional maturation. Knowledge [Page 962]of human development is of great significance to a range of professions such as psychology, counseling, education, and health care.

Lifespan developmental theories offer a framework for understanding normative patterns of development. At the individual level, such knowledge supports the early identification of developmental difficulties, including diagnosis of intellectual and developmental disorders. Public policy and practice is informed by better understanding the needs of the population ...