Engeström's Expansive Triangle

(Extracted from Learning by Expanding (1987))
Engeström holds that this model is the smallest and most simple structural form that still preserves the essential unity and integral quality of any human activity. With the help of this model, activity can be analyzed in its inner dynamic relations and historical change. It is a useful tool for identifying the deep seated contradictions that give rise to surface level discoordination and conflict. Activity Theory sees these contradictions as sources of learning and development. Real practices are practically always in the process of working through some of such contradictions even though these are experienced negatively by participants who always wish to see the activity system "running smoothly". But change is the only constant in a system.

• An activity is actually a system whole in the sense that all elements have a relationship to other elements. It is the fundamental context of study.


• The relation between subject and object is mediated by tools (or instruments), that between subject and community is mediated by rules (norms or constraints), and that between object and community is mediated by division of labor.


• Each of the mediating elements is historically formed and opened to further development. Ever since an activity is formed, the corresponding mediating elements are continuously reconstructed. This development is driven by different contradictions, it is not a smooth and linear process but uneven and discontinuous one.


• An acivity has an active subject (an individual or collective), who understands the object (motive) of the activity. However, not all participants (community) invovled in an activity necessarily understand the motive of the activity in which they are participating or even recognize the existence of one.


• As the contradictions (structural tensions) of an activity system are aggravated over a period of time, some individual participants begin to question and deviate from its established norms.