The Ecological System Theory (Bronfenbrenner, 1994) conceives the ecological environment in which an individual lives as a set of five systems, each of which nested inside another, with the Microsystem being the innermost and the Chronosystem the outermost.

1. MICROSYSTEM – The Immediate Environment
Consists of activities, social roles and interpersonal relations that the individual directly experience in a given setting, such as family, school, peer group and workplace.

2. MESOSYSTEM – The System of Microsystems
Comprises the connections between two or more settings that surround the individual, such as the relations between home and school, between home and workplace…

3. EXOSYSTEM
Comprises the connections between the settings that surround the individual (home, school, peer group…) and external settings which indirectly influences the individual’s life (parents’ workplaces, the neighborhood…).

4. MACROSYSTEM
Encompasses comprehensive patterns of the microsystems, mesosystems, and exosystems of the environment in which the individual lives, such as national regime, belief system, knowledge, infrastructure, lifestyles, hazards…

5. CHRONOSYSTEM
Includes the changes or consistency over time in the characteristics of the individual and of the environment in which they live, such as changes in family structure, socioeconomic status, employment, place of residence…

On proposing the theory, Bronfenbrenner emphasized the importance of studying human development through the movements of its surrounding environments and their interactions, citing research evidence for the influences of each of the systems on individual lives. One given example was Elder’s study “Children in the Great Depression”, which reported that young people experiencing the decline of their home economy during their adolescence – a facet of the Chronosystem – seemed to develop a more robust sense of achievement as well as career orientation compared to those who experiencing it as small children (Elder, 1974, as cited in Bronfenbrenner, 1994). Another mention was Epstein’s findings in 1983, which suggested that the closer collaboration between teachers and parents in elementary school – part of the Mesosystem – contributed to the higher levels of autonomy and achievement that the students would obtain in high school (Estein, 1983a, 1983b, as cited in Bronfenbrenner, 1994). And beyond scientific realm, we all can recognize the impacts of the ecological systems in real life by relating with our own experiences as well as with our observations of others.

In consideration of heredity, Bronfenbrenner proposed an extension of the Ecological System Theory, termed as a “bioecological model”. The model acknowledges the role of heritability, but adds that heritability itself is under the influence of the environment, arguing that the process of heritability varies in a magnitude of potentials, and which level of potential its manifestations would reach depends on the quality of environmental conditions surrounding it. Despite its attempt to combine biology and environment in explaining human development, the model fails to provide in-depth insights about biological factors, while relying largely on the conceptualization of ecological contexts. Because of this limitation, Bronfenbrenner’s Ecological System Theory is regarded as just another complementary, rather than a comprehensive, perspective in the area of developmental psychology (Shaffer & Kipp, 2014).

Bronfenbrenner, U. (1994). Ecological models of human development. In Husen T. & Postlethwaite, T. N. (Eds.), International Encyclopedia of Education (2rd ed., Vol. 3, pp. 3-44). Oxford, UK: Elsevier.

Shaffer & Kipp (2014). Developmental Psychology (8th ed.). Belmont, CA: Wadsworth Cengage Learning