Thursday, January 19, 2006

Complexity and Social Networks

Do you know that anyone on earth can be connected to any other person through a chain of acquaintances that has no more than five intermediaries ? (Six degrees of separation theory). Do you know that the size of a genuine social network is limited to about 150 ? (Dunbar Number).
What is the network model of my organization ? What are the emerging patterns and dynamics ? Is my company well adapted to its market ? How can I locate key players ? …
Social network theory views humans relationships as a network of agents connected through various acquaintances. The analysis of these networks is crucial for a better understanding in sociology, anthropology, organizational studies, economy and finance, etc. Within these domains, Internet plays a central role since online social networks (forums, chats, blogs, wikis, online games, etc.) are becoming increasingly popular. We can model such networks of interacting entities using classical approaches in the science of complexity: cellular automata, random networks, multi-agent system, etc. However, it appears to me that a hierarchical modeling could constitute a better approach (more precisely a hierarchy of intricated small-world agent-based networks). Let me try to explain why. First, it seems obvious that only multiple levels can reflect the complexity of real cases. At the lower level there is always a communication medium. For online social networks, this physical network is a graph of connected computers and servers, portable devices, mobile phones, etc. On top of this physical network, there are many possible different levels: individuals but also organizations, companies, countries, nations, etc., and other ones like social, cultural communities or any other forms of communities of interest. My second argument is that "classical" models are simple and universalist, let say: easy to model, to code and to understand. However, even they provide very interesting results in terms of emerging global dynamics and trends, they are generally inadequate for modeling a specific case to obtain practical informations. I think that the study of hierarchical multi-agent systems for modeling (online) social networks represents a promising approach and could contribute to give useful results in many real-world applications.


stephane said...

J.C., could you give some links about this 'hierarchical models'? Where could one find good information to begin with?

You may find an useful implementation of these 'social networks' on a site for Business Relations:

This is really interesting to see it because you can get a list of all the people that connect you to another given person.


Justin Lyon said...

J.C. Are you familiar with the work of Dr. Suarez at Trinity University in San Antonio on hierarchiacly decomposed agents?

jcheudin said...

To be honest, I am not an expert in social networks (see some of the projects we are working on in the right part of this site). This post is the result of a preliminary bibiographical study and my personnal view of what seems to me a promising research approach in this field. However concerning hierarchical modelling, we use this pporach in the M31 project (cosmological complexity). A paper will be submitted soon...

LePireDesBlogs said...

That's the point! There is a lot of work with political aspects, don't you think?
Of course the main point is the loneliness of each of us. Are the "new social Networks" an answer or just a dream, a way to simulate? An other way to use every one?
may be, may be not..!
See you.

bushido said...

i am rather interested by social network used in compgny management based on personal interaction models. Not only political relationship ariing in human interaction in the business world. The point is how human behaviour uses the interactions with others in a complex business area. Is any body can help me on biography or works done on the topic.Thank you in advance

jcheudin said...

An introductory bibliography on social networks is: said...

I would recommend visiting the Blog by Harvard's Program on Networked Governance headed by David Lazer.

The Complexity and Social networks blogs covers various issues:

You can find even more information on SNA by Ines mergel here:

Justin Lyon said...


These are great links. Thank you for sharing them!

You can find out more information about Simudyne and what we are doing with hierarchical models by reading Dr. Dante Suarez's theoretical paper here: