The basic assumption of our approach is the interpretation of organization in real complex systems in terms of the attractors of the dynamics of a formal model system. By contrast, social sciences, and some economists try to characterise institutions in connection with cooperation and risk aversion issues. In some sense standard economical theory ignores dynamics and is mostly based on equilibrium. In fact real markets, wether financial markets or everyday life markets where ordinary goods are exchanged display a lot of organisation in relation to information available to the agents. The simplest models of cultural diffusions, such as new technology adoption or commercial products are inspired from epidemiology.
Diffusion is based on a contagion process occuring on the occasion of random encounters.
Random encounters result in an S shaped dynamics for the adoption rate. Things get more intricate when one takes into account the existence of social networks which support influence propagation and the fact that some innovation does not benefit equally to all agents. For binary choices, the dynamics is described by the use of inhomogeneous automata networks. When only one neighbour is enough to transmit information, percolation phenomena control the dynamics. When economic adjustments are introduced, self-organised criticality and non gaussian fluctuations are observed.