Complex Systems in Human and Social Sciences


1/ Objectives and Expectations:

In the last fifteen years, great progress has been made in the study of complex systems, with regard to methods, formalisation and modelling tools.

Complex systems are defined as systems composed of a large number of different elements interacting in a non-trivial way (non-linear interactions, feedback loops, etc). Such systems are characterised by the global emergence of new functional properties.

The field of application of the theory of complex systems is extremely vast: it concerns broad sectors of physics (disordered systems, percolation phenomena, etc.), biology (gene-protein systems, the immune system, ecological systems, etc.), as well as all cognitive sciences, economics and social sciences. In particular, most areas of research in the field of human and social sciences address complex systems. The complex systems approach concerns many different disciplines, and it is thus tempting to apply these tools created for physics and biology to all disciplines concerned by complex objects. Obviously these concepts and methods might have to be adapted through comparison with the specifics of social systems (bounded rationality, beliefs, institutions etc).

The purpose of the programme is to stimulate research in this field and extend it to a greater number of human and social sciences, by encouraging researchers to conduct theoretical analyses and to design models using empirical data and issues specific to each discipline.

This stakes involved in this research are considerable, especially for socio-economic disciplines as they can contribute greatly to better understanding and control of the evolution of our society. Thus, besides their purely theoretical interest, research on complex systems in human and social sciences can applied to operation research and management, especially under circumstances where decisions involve many different players and concern agents with bounded rationality, whose individual objectives do not necessarily coincide with an overall optimal objective.

2/ National, European, International Context:

The first approaches to "complex systems" date back to the 40s with the self-replication problem (Von Neumann) and formal neuronal networks (McCullochs and Pitt). In the 70s and 80s, mathematicians (Thom), physicists working in non-linear dynamics (Haken, Prigogine) and statistical physics (Anderson) became interested in the phenomena of self-organisation, in view of generalising to biological systems the idea that the emerging global properties of this type of system could not be obtained directly by averaging the properties of their interacting elements, as for linear systems. The development of connectionism in the 80s marked an important step, with the conjunction of methods used by physicists (Hopfield, Amit, etc), neurophysiological models (neuromimetic networks), and work in the area of cognitive science (McCleland and Rumelhart). On the other hand, the Santa Fe Institute has been recognised as a driving force in the application of complex system methods and theory to biological systems. In the 90s, the development of logical-symbolic methods that could take agents' capacities and strategies into account led to the modelling of bounded-rationality multi-agent systems (Axelrod, Epstein, etc), which directly target the study of social phenomena (emergence of conventions, evolution of economic systems, etc). An entire range of methods and techniques are currently available for analysing the complex behaviours of human communities. Adapting these methods and techniques to the different disciplines of human and social sciences poses a major challenge for the years to come.

In France, several communities of modellers, mathematicians, physicists and computer experts are already working in this direction in close collaboration with biologists, cognitive scientists and economists.

3/ Targeted Communities:

The programme targets four types of research communities:

1. Complex system theorists and modellers. Our aim is to foster the application of existing techniques and the development of new technique to address specific issues in the various human and social sciences (working closely with researchers in these areas); 2. Researchers in SHS disciplines such as economics and linguistics, which are already accustomed to modelling, to develop research projects using a complex system approach in their disciplines; 3. Researchers in SHS disciplines such as anthropology and sociology, which until now have remained in France outside this movement, raising awareness about these tools in order to facilitate their use in their own reasearch area; 4. Applied researchers working in coordination with companies that have actual data, often a missing link which would allow to build realistic models.

4/ Program Description:

The program covers a number of areas corresponding to the various disciplines of human and social sciences, including: - Cognitive systems, as seen from the perspective of emergence: such as perception, reasoning, decision-making and action. - Economic systems (markets, firms, etc), as systems whose overall dynamics result from the interaction of agents with bounded rationality and different objectives. - Origin, diversification and evolution of languages: emergence of linguistic conventions, internal transformation processes (grammaticalisation, reanalysis, etc.) and external transformation processes (lexical diffusion, borrowing, etc.). - Social organisation of space: transportation systems, demographic transfers, etc. - Socio-political institutions: their emergence and evolution. - Dynamics of ideas: emergence and diffusion of representation and belief systems, knowledge development, etc.

Initial applications to the call for proposals (May 2003) covered all of these subjects. Grants were allocated to teams working on the first four subjects in July 2003. Part of the funding will support coordination activities, such as website development (http//, seminars and thematic one day meetings, as well as two "summer schools" in 2004.

5/ Collaborations:

This CNRS program is conducted in coordination with the Ministry of Research and New Technology, which launched an Incentive Concerted Action (ACI) on the same subject and under the same title. The CNRS program and the Ministry's ACI share a common steering committee and science board.

7/ Program Direction

(scientific director, program director, members of the steering committee):

  • Scientific Director: Jean-Marie Hombert
  • Program Director: Gérard Weisbuch, CNRS Research Director

Steering Committee:

  • Alain Peyraube, CNRS Research Director
  • Richard Topol, CNRS Research Director
  • Bernard Victorri, CNRS Research Director
  • Hervé Zwirn, CNRS Associate Research Director