Inverse Learning in $2\times2$ Games: From Synthetic Interactions to Traffic Simulation
Daniela Aguirre Salazar, Firas Moatemri, Tatiana Tatarenko
TL;DR
This work tackles inverse game-theoretic learning for 2x2 normal-form games, aiming to recover latent utilities from observed joint actions in domains such as traffic. It introduces two maximum-likelihood frameworks: CE-ML, which leverages the closed-form 2x2 CE polytope to fit utilities and CE mixtures, and LBR-ML, which treats behavior as the stationary distribution of logit best-response dynamics to capture bounded rationality. The methods are evaluated in synthetic Chicken-Dare games and SUMO-based traffic simulations, showing that CE-ML excels when data align with correlated equilibrium and LBR-ML is more robust under uncoordinated or noisy conditions, with ICE serving as a weaker baseline in non-CE regimes. The findings highlight a practical trade-off between interpretability and dynamic realism, and point to potential extensions to larger-scale, heterogeneous, or online-estimation settings for traffic and multi-agent systems.
Abstract
Understanding how agents coordinate or compete from limited behavioral data is central to modeling strategic interactions in traffic, robotics, and other multi-agent systems. In this work, we investigate the following complementary formulations of inverse game-theoretic learning: (i) a Closed-form Correlated Equilibrium Maximum-Likelihood estimator (CE-ML) specialized for $2\times2$ games; and (ii) a Logit Best Response Maximum-Likelihood estimator (LBR-ML) that captures long-run adaptation dynamics via stochastic response processes. Together, these approaches span the spectrum between static equilibrium consistency and dynamic behavioral realism. We evaluate them on synthetic "chicken-dare" games and traffic-interaction scenarios simulated in SUMO, comparing parameter recovery and distributional fit. Results reveal clear trade-offs between interpretability, computational tractability, and behavioral expressiveness across models.
