Ecological systems theory was introduced by Urie Bronfenbrenner in 1979, and was later expanded on several times. The theory describes child development in terms of different environmental systems (microsystem, mesosystem, exosystem, macrosystem and chronosystem), which are all graphically presented as different ‘layers’ around the individual, apart from the chronosystem which is the dimension of time. The development of the child is the outcome of progressive, continuous interaction with the different systems, and he or she learns behaviours that are suitable and useful when interacting with each system.
Bjorklund, D. F., Blasi, C. H. (2011). Child and Adolescent Development: An Integrated Approach. Belmont, CA: Cengage Learning. (pp. 68-70)