Ecological Theory of Development

There have been many different approaches to explaining development, but one especially has tried to deal with the importance of the environment without ignoring the uniqueness of the individual. Urie Bronfenbrenner, and more recently along with Pamela Morris, has developed what is called an experimental ecology of human development or an ecological theory of human development. Within this model he stresses the importance of the developing person in his or her surrounding environment. He defines the phrase ecology of human development as the study of “the progressive, mutual accommodation, throughout the life span, between a growing human organism and the changing immediate environments in which it lives.”

His basic argument is that traditional studies in human development are very rigorous and tightly controlled. While this can be a benefit, the studies are also very limited in scope because many of these experiments take place in settings that are unfamiliar to the participants  and  artificial  in  their  construction.  In other words, they don’t very accurately represent what the real world is about; in Bronfenbrenner’s earlier and own words, developmental research has been “the study of the strange behavior of children in strange situations for the briefest possible period of time.”

Because he is so concerned with the qualities and characteristics of the environment, part of his ecological model defines a series of structures that are “nested” within one another. In his earliest works, he described four such structures. These structures nest or “fit” within each other, beginning with the microsystem (as he points out much like the stacking Russian dolls that disappear within one another).

The microsystem reflects the immediate setting that contains the person. Keeping in mind how our immediate setting changes throughout the day, the microsystem in which we find ourselves changes as well. Although the library might be the microsystem in which we found ourselves late at night, our office or classroom might be the parallel microsystem during the day.

All microsystems have three different dimensions. The first is the physical space and activities within the microsystem such as the lighting over our desk or the temperature of the classroom during a test. The second is the people and their roles who are part of the microsystem such as our roommate or our classroom teacher. Finally, the third is the interaction between the people in the microsystem and the person. At one time, for example, we might be angry with a roommate who does not do his or her assigned tasks. At another time, we might act like best friends.

The second level, called the mesosystem, focuses on the relationships between the different settings that the person is in during different times in development. The mesosystem focuses on interrelations among microsystems. For example, the mesosystem for college freshmen might consist of the dining hall, the classroom, home, and the intramural softball field.

The third element is the exosystem. Bronfenbrenner believes that the exosystem is a set of specific social structures that do not directly contain the individual, but still have an impact on the person’s development. These structures “influence, delimit, or even determine what goes on” in the microsystem of the developing individual. The individual does not participate in these settings, but they do have a direct impact on his or her behavior. For example, an exosystem might be the doctor’s office, the teacher’s lounge, or grandma’s house. These are all places with an indirect impact on the person’s development.

The last element or structure in his model is called the macrosystem. It consists of all the elements contained in the micro-, meso-, and exosystems, plus the general underlying philosophy or cultural orientation within  which  the  person  lives. As  Bronfenbrenner says, these are the “overarching institutional patterns of the culture or subculture, such as the economic, social, educational, legal, and political systems of which local micro, meso, and exosystems are the concrete manifestations” (p. 8).

This early model of the ecology of human development helps us in two primary ways as far as understanding human development. First, it places the interaction between nature and nurture in a very clear and easily definable context of one of the four systems discussed above. Second, it encourages us to move away from laboratory-based settings and begins to examine development in the “natural stream” of when and where it occurs. More and more scientists who study human development are emphasizing the qualitative nature of changes and using such methods that reflect that emphasis—away from the more tightly controlled laboratory study.

But, as with all good scientists, Bronfenbrenner has moved on. Along with Morris’s help, he has taken the next step and further developed their ideas placing an emphasis on several new and complimentary ideas. The primary change in the ideas presented almost 20 years ago, and now referred to as part of a bioecological model, involves proximal processes (or interactions in the immediate environment).

  1. In order for the person to develop, he or she needs to be an active contributor to the environment.
  1. These activities and contributions have to take place on a regular basis and over an extended period of time.
  1. These activities also need to become more complex over time—doing the same thing as before will not act as the “engine” of development that Bronfenbrenner and Morris emphasize.
  1. The process  of  development  is  a  reciprocal  one where each member of a dyad or group influences each other member.
  1. While interactions with people are very important, interactions with objects are important as well.
  1. The importance  and  role  of  proximal  processes change over time as the individual and environment change as well.

Bronfenbrenner’s original model has clearly expanded to further emphasize the importance of the environment and the interaction between the individual and his or her environment. It is a rich display of ideas and the importance of the role of our social world and its influence upon us.


  1. Bronfenbrenner, (1977). Toward an experimental psychology of human development. American Psychologist, 32, 513–531.
  2. Bronfenbrenner, , & Morris, P. A. (1998). The ecology of developmental processes. In W. Damon & R. Lerner (Eds.), Handbook of child psychology (5th ed.). New York: Wiley. Urie Bronfenbrenner.  (n.d.). Retrieved from