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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.

Merge and Conquer: Evolutionarily Optimizing AI for 2048

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 + points per cycle, ) 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 =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.
Paper Structure (15 sections, 5 figures)

This paper contains 15 sections, 5 figures.

Figures (5)

  • Figure 1: Program Flow of the MCTS Refinement System
  • Figure 2: Metaprompting system, Average Score vs. Cycle Number; average score per round with 95% confidence intervals over cycle progression. The red dashed line represents the trend (slope: 12.3 points/round)
  • Figure 3: Altered Value Function with Rollback, Average Score vs. Cycle Number; average score across training cycles with 95% confidence intervals. The red dashed line highlights a positive linear trend ($\rho$ = 0.607), indicating performance improvement as training progresses.
  • Figure 4: Distribution of highest tiles.
  • Figure 5: Score range distribution.