AI & Computational Science

AI Language Models Show Hidden Biases When Solving Logic Puzzles

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Researchers developed PRIME, a new evaluation framework using logic grid puzzles to detect subtle social biases in large language models during complex reasoning tasks. Testing multiple AI models on gender stereotypes, they found that models consistently performed better when puzzle solutions aligned with stereotypical associations rather than anti-stereotypical or neutral scenarios. The framework enables automatic generation and verification of puzzles with varying complexity levels, allowing controlled comparison across stereotypical, anti-stereotypical, and neutral variants.


This research reveals that current safety measures fail to prevent implicit biases in AI reasoning processes, even when overt biased outputs are suppressed. The findings are particularly significant for applications requiring fair logical decision-making, such as hiring systems, loan approvals, and diagnostic tools where subtle stereotypical reasoning could perpetuate discrimination.


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arXiv:2511.06160v2 Announce Type: replace
Abstract: While recent safety guardrails effectively suppress overtly biased outputs, subtler forms of social bias emerge during complex logical reasoning tasks that evade current evaluation benchmarks. To fill this gap, we introduce a new evaluation framework, PRIME (Puzzle Reasoning for Implicit Biases in Model Evaluation), that uses logic grid puzzles to systematically probe the influence of social stereotypes on logical reasoning and decision making in LLMs. Our use of logic puzzles enables automatic generation and verification, as well as variability in complexity and biased settings. PRIME includes stereotypical, anti-stereotypical, and neutral puzzle variants generated from a shared puzzle structure, allowing for controlled and fine-grained comparisons. We evaluate multiple model families across puzzle sizes and test the effectiveness of prompt-based mitigation strategies. Focusing our experiments on gender stereotypes, our findings highlight that models consistently reason more accurately when solutions align with stereotypical associations. This demonstrates the significance of PRIME for diagnosing and quantifying social biases perpetuated in the deductive reasoning of LLMs, where fairness is critical.

Source: Evaluating Implicit Biases in LLM Reasoning through Logic Grid Puzzles