This article explores and substantiates the hypothesis that capital investment and real output in national economies are instrumental to the optimization of labour markets, i.e. human societies are oriented, most of all, on shaping their labour markets so as to assure an equilibrium between demographic growth and the set of social roles available. An original method, largely based on the Interface Theory of Perception, studies economic systems as manifestations of collective intelligence, learning by evolutionary tinkering with itself. An artificial neural network is used to study economic systems as Markov chains of states, and to discover their structuring σ-algebras, which turn out being oriented mostly on optimizing the compensation of labour and the average workload per person per year.