The Invisible Hand of Stability: Dynamics of Decentralized Decision Making
Geelon So (UC San Diego)
Monday, January 26th, 2026, 2-3pm
Abstract:
The division of labor enables us to build complex human and machine systems. But, decentralization can also come with the Price of Anarchy. As in the Prisoner's Dilemma, constraints on communication and coordination can result in jointly suboptimal decisions—or, collective irrationality.
Nash equilibria describe collective behavior that may have long-term relevance. But, not all equilibria are learnable (dynamically stable). It is well-established that learnability and collective rationality are independent for strict equilibria.
We show that for non-strict Nash equilibria, the opposite is true: learnability and collective rationality are closely related. In fact, for polymatrix games, they are equivalent. Thus, we recover Adam Smith’s Invisible Hand, where individually utility-seeking dynamics robustly behave as if the players were collectively rational.
This talk is based on a work with Yian Ma, https://arxiv.org/abs/