Merge and Conquer: Evolutionarily Optimizing AI for 2048
Maggie Bai, Ava Kim Cohen, Eleanor Koss, Charlie Lichtenbaum
TL;DR
The paper tackles optimizing AI for the stochastic game 2048 using evolutionary training without fine-tuning or RL. It contrasts a two-agent metaprompting framework with a single-agent value-function refinement for MCTS, incorporating a rollback mechanism. The single-agent approach yields substantial gains (average +$473.2$ points per cycle, $\rho=0.607$) and visible strategic growth, whereas the two-agent framework shows limited improvement, illuminating limits of meta-prompting for self-improvement. The results highlight the potential of evolutionary refinement, particularly code-based function optimization with rollback, for robust decision-making in non-deterministic environments and suggest directions to stabilize learning further.
Abstract
Optimizing artificial intelligence (AI) for dynamic environments remains a fundamental challenge in machine learning research. In this paper, we examine evolutionary training methods for optimizing AI to solve the game 2048, a 2D sliding puzzle. 2048, with its mix of strategic gameplay and stochastic elements, presents an ideal playground for studying decision-making, long-term planning, and dynamic adaptation. We implemented two distinct systems: a two-agent metaprompting system where a "thinker" large language model (LLM) agent refines gameplay strategies for an "executor" LLM agent, and a single-agent system based on refining a value function for a limited Monte Carlo Tree Search. We also experimented with rollback features to avoid performance degradation. Our results demonstrate the potential of evolutionary refinement techniques in improving AI performance in non-deterministic environments. The single-agent system achieved substantial improvements, with an average increase of 473.2 points per cycle, and with clear upward trends (correlation $ρ$=0.607) across training cycles. The LLM's understanding of the game grew as well, shown in its development of increasingly advanced strategies. Conversely, the two-agent system did not garner much improvement, highlighting the inherent limits of meta-prompting.
