Caroline Wang

Researchers at UT-Austin and Google Model Human Decision-Making in Rock-Paper-Scissors

Researchers from UT-Austin and Google used AlphaEvolve, an evolutionary code-optimization method, to synthesize interpretable Python programs that predict move-by-move decisions of LLMs and humans playing rock-paper-scissors against bots. They found that Gemini 2.5 Pro, Gemini 2.5 Flash, and GPT-4.1 share similar sequential-pattern-tracking strategies that are more systematic than typical human play, while GPT-OSS 120B and humans relied on simpler opponent-move-frequency heuristics. The study demonstrates that code synthesis from behavioral data can serve as an interpretability tool for LLM decision-making, revealing that LLMs do not simply mimic human strategies.