Bounded rationality and animal spirits: a fluctuation-response approach to Slutsky matrices

The Slutsky equation, central in consumer choice theory, is derived from the usual hypotheses underlying most standard models Economics, such as full rationality, homogeneity, and absence of interactions. We present a statistical physics framework that allows us to relax assumptions. first derive general fluctuation-response formula relates matrix spontaneous fluctuations consumption rather than response changing prices budget. then show that, within our hypotheses, symmetry remains valid even when agents are only boundedly rational but non-interacting. propose model where influenced by others, leading phase transition beyond which dominated herding (or `"fashion") effects. In this case, individual no longer symmetric, for fully agents. vicinity features peak asymmetry.