ON THE INCOMPLETE ARCHITECTURE OF HUMAN-D EVELOPMENT - THE 4TH AGE

Drawing on both evolutionary and ontogenetic perspectives, the basic b iological-genetic and social-cultural architecture of human developmen t across the life span is outlined. Three governing principles are inv olved. First, evolutionary selection evinces a negative age correlatio n and, therefore, genome-based plasticity and biological potential dec rease with age. Second, for growth-aspects of human development to ext end further into the life span, culturebased resources are required at ever increasing levels. Third, because of age-related losses in biolo gical plasticity, the efficiency of culture is reduced as life-span de velopment unfolds. Joint application of these principles suggests that the life-span architecture becomes more and more incomplete with age. With regard to life-span outcomes, degree of completeness can be defi ned as the ratio between ga;ns and losses in functioning. Two examples are given to illustrate the implications of the lifespan architecture proposed. The first is a general theory of development involving the orchestration of three component processes: selection, optimization, a nd compensation. The second example considers the task of completing t he life course in the sense of achieving a positive balance between ga ins and losses for all age levels. This goal is more and more difficul t to attain as human development is extended into old age.