Urie Bronfenbrenner

Urie Bronfenbrenner (April 29, 1917-September 25, 2005) was a renowned psychologist and a co-founder of the U.S. national Head Start program.

Generally regarded as one of the world's leading scholars in the field of developmental psychology, his primary contribution was his Ecological Systems Theory, in which he delineated four types of nested systems. He calls these the microsystem (such as the family or classroom), the mesosytem (which is two microsystems in interaction), the exosystem (which is a system influencing development, i.e., parental workplace), and the macrosystem (the larger cultural context). Each system contains roles, norms and rules that can powerfully shape development. The major statement of this theory, The ecology of human development (1979) had widespread influence on the way psychologists and others approached the study of human beings and their environments. It has been said that before Bronfenbrenner, child psychologists studied the child, sociologists examined the family, anthropologists the society, economists the economic framework of the times and political scientists the structure. As the result of Bronfenbrenner's groundbreaking work in "human ecology," a field that he created, these environments - from the family to economic and political structures - were viewed as part of the life course from childhood to adulthood. Bronfenbrenner's "bioecological" approach to human development broke down barriers among the social sciences and built bridges among the disciplines that have allowed findings to emerge about which key elements in the larger social structure and across societies are vital for optimum human development.

"At his death, Bronfenbrenner was the Jacob Gould Schurman Professor Emeritus of Human Development and of Psychology at Cornell University, where he spent most of his professional career."