Heterogeneity, interaction and emergence: effects of composition

The present paper emphasises that socioeconomic systems are complex systems due to two entangled categories characterising their constituents: heterogeneity and interaction as the main sources of complexity and emergence. This perspective is developed by reasoning on the double-face problem of microfoundation and aggregation in macroeconomic modelling taking care of heterogeneity, interaction and composition effects of individual behaviours into the emergence of macroscopic phenomena. With reference to the literature of this field, based on the statistical physics perspective in conjunction with the agent based modelling, an approach is discussed to analyse complex systems dynamics by means of a restricted set of equations explaining the dynamics of the drifting path trajectory and the distribution of fluctuations.