🤖 AI Summary
This study addresses a critical gap in the literature by jointly modeling learning mechanisms and heterogeneous preferences—factors often examined in isolation—in financial markets. It proposes a novel multi-agent reinforcement learning framework for an artificial financial market, where traders exhibit heterogeneity in risk aversion, time discounting, and information acquisition capabilities. These agents adaptively learn through interaction and evolve distinct trading strategies over time. The model successfully replicates key stylized facts of real financial markets, including fat-tailed return distributions and volatility clustering. By demonstrating how macro-level market dynamics emerge from micro-level heterogeneity and adaptive learning, this work provides a computational instantiation and empirical validation of the Adaptive Markets Hypothesis.
📝 Abstract
Agent-based models provide a constructive approach to studying emergent dynamics in life-like systems composed of interacting, adaptive agents. Financial markets serve as a canonical example of such systems, where collective price dynamics arise from individual decision-making. In this modeling tradition, investor behavior has typically been captured by two distinct mechanisms -- learning and heterogeneous preferences -- which have been explored as separate paradigms in prior studies. However, the impact of their joint modeling on the resulting collective dynamics remains largely unexplored. We develop a multi-agent reinforcement learning framework in which agents endowed with heterogeneous risk aversion, time discounting, and information access learn trading strategies interactively within an artificial market. The experiment reveals that (i) learning under heterogeneous preferences drives agents to develop functionally differentiated strategies through interaction, rather than trait-specific rules, resulting in role specialization, and (ii) the interactions by the differentiated agents are essential for the emergence of realistic market dynamics such as fat-tailed price fluctuations and volatility clustering. Overall, this study demonstrates that the joint design of heterogeneous preferences and learning mechanisms enables the synthesis of an artificial market in which adaptive interactions drive the self-organization of a market ecology, providing a computational realization of the Adaptive Market Hypothesis.