A bridge between liquids and socio-economic systems: the key role of interaction strengths

One distinctive and pervasive aspect of social systems is the fact that they involve several kinds of agents. Thus, in order to draw parallels with physical systems one is led to consider binary (or multi-component) compounds. Recent views about the mixing of liquids in solutions gained from neutron and X-ray scattering show these systems to have a number of similarities with socio-economic systems. It appears that such phenomena as rearrangement of bonds in a solution, gas condensation, and selective evaporation of molecules can be transposed in a natural way to some socio-economic phenomena. These connections provide with a novel perspective for looking at social systems which we illustrate through examples. For instance, we interpret suicide as an escape phenomenon and in order to test this interpretation we consider social systems characterized by very low levels of social interaction. For these systems suicide rates are found to be 10 to 100 times higher than in the general population. Another interesting parallel concerns the phase transition that occurs when locusts gather together to form swarms which may contain several billion insects. What hinders the thorough investigation of such cases from the standpoint of collective phenomena that we advocate is the lack or inadequacy of statistical data; up to now socio-economic data were collected for completely different purposes. Most essential, for further progress, are the statistics which would permit to estimate the strength of social ties and interactions. Once adequate data become available, rapid advancement may be expected. At the end of the paper, we will discuss whether or not the ergodic principle applies to social systems.