Robert Havighurst introduced the concept of developmental tasks in the 1950s. Developmental tasks are tasks that arise during certain periods of life that lead to happiness if successfully achieved and difficulty if failed. Havighurst identified six major age periods and associated developmental tasks with each. Developmental tasks are based on the needs and norms of society and include tasks like learning to walk in infancy, academic skills in childhood, relationships in adolescence, occupations and family in early adulthood, and adjusting to aging in later life. Failure to successfully complete developmental tasks can result in unhappiness and problems with later tasks.