An Ever-Changing System

The environment is not a static force that affects children in a uniform way. Instead, it is ever-changing. Important life events, such as the birth of a sibling, the beginning of school, a move to a new neighborhood, or parents’ divorce, modify existing relationships between children and their environments, producing new conditions that affect development. In addition, the timing of environmental change affects its impact. The arrival of a new sibling has very different consequences for a homebound toddler than for a school-age child with many relationships and activities beyond the family.

Bronfenbrenner called the temporal dimension of his model the chronosystem (the prefix chrono- means “time”). Life changes can be imposed on the child, as in the examples just given. Alternatively, they can arise from within the child because as children get older, they select, modify, and create many of their own settings and experiences. How they do so depends on their physical, intellectual, and personality characteristics and their environmental opportunities. Therefore, in ecological systems theory, development is neither entirely controlled by environmental circumstances nor driven solely by inner dispositions. Rather, children and their environments form a network of interdependent effects.