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An ant colony as an example of a complex system
An ant colony as an example of a complex system

Introduction to complexity

This article deals with the meaning of complexity and the most salient characteristics of complex systems.

In the previous step we have given a definition of complexity. One has to be aware that there is not just one generally accepted definition in the literature about complexity. We favour a rather general definition of complexity:

Complexity is a characteristic of a system. A system is a set of elements that are related. The system is complex if the elements interact; that is, they respond to each other. They may also respond to the outside world.

The elements are heterogeneous or diverse. Page (2011) discusses the different forms and functions of diversity in complex systems. The interactions in complex systems are driven by this heterogeneity. Take a market economy. If all people would have the same skills, preferences and endowments, there would be little need for market transactions.

The interactions between the elements in a complex system may be generated by fixed and relatively simple rules of the behaviour of the elements. In case the elements adjust themselves to their environment or on the basis of their interaction with other elements, we talk about adaptive complex systems. Like how the ants in the picture react to their environment and each other and keep adapting to changing circumstances.

The elements can be anything from particles to human beings. A complex system of human beings or organisations/institutions of human beings is a social complex system. We devote special attention to social complex systems, because they have their own characteristics. In the next activity you will learn about social complex systems.

For an broader account of the definition of complexity, we refer to Lloyd (2001), Mitchell (2009) or Page (2011)

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This article is from the free online course:

Decision Making in a Complex and Uncertain World

University of Groningen

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