ISSN : 1229-0718
A concern of the system theory and chaos theory has recently increased in the field of psychology. The present work is arcing at applying these theories to the development of a psychological system under the assumption that a psychological system is an open system. At first the phenomena of the development of an open system - various social and natural systems that interact with the environment - are summurized and discussed to have five characteristics. These five developmental phenomena of an open system are theoretically compared to the characteristics of the change of the Piaget's cognitive system. They are also applied to explain the empirical data on the change of the social networks (social emotional support systems) of 14 years old Korean and German adolescents.