Language Models Compare Quantities Using Number-specific and Unit-specific Heuristics
arxiv:2606.03982
Reasoning and the "physics" of language models · 2026-06-02
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Contents
- Language Models Compare Quantities Using Number-specific and Unit-specific Heuristics
- Abstract
- 1 Introduction
- 2 Task Formulation and Overall Experimental Setup
- 2.1 Task Formulation
- 2.2 Overall Experimental Setup
- 3 Behavioral Observation: LMs Become Less Accurate Near the Boundary
- 3.1 Experimental Setup
- 3.2 Results
- 4 Cue-Combination Hypothesis: Quantity Decisions Depend on Cue Agreement
- 5 Surrogate Analysis: Number and Unit Differences Best Predict LM Behavior
- 5.1 Experimental Setup
- Implementation details.
- 5.2 Results
- 6 Causal Analysis: Number and Unit Differences Steer LM Decisions
- 6.1 Experimental Setup
- 6.2 Results
- 7 Related Work
- 8 Conclusion
- Limitations
- Ethical Considerations
- Appendix A Task Formulation and Overall Experimental Setup
- A.1 Prompt Templates
- A.2 Choice of Prompt for Main Analyses
- A.3 Generation and Evaluation
- A.4 Effects of Number Formatting, Unit Notation, and Tokenization
- A.5 Motivation for Analyzing the Quantity Margin in Log Space
- Appendix B On the Terms “Heuristic”, “Heuristic Aggregation”, and “Bag of Heuristics”
- Heuristic.
- Heuristic Aggregation.
- Appendix C Behavioral Observation: LMs Become Less Accurate Near the Boundary
- C.1 Results Across LMs
- C.2 Effects of Prompt Templates
- C.3 Effects of Unit Notation
- C.4 Generated Outputs from Reasoning LMs
- Appendix D Cue-Combination Hypothesis: Quantity Decisions Depend on Cue Agreement
- Appendix E Surrogate Analysis: Number and Unit Differences Best Predict LM Behavior
- E.1 Surrogate Feature Design
- E.2 Additional Surrogate Results
- Appendix F Causal Analysis: Number and Unit Differences Steer LM Decisions
- F.1 Distributed Alignment Search
- F.2 Robustness Across LMs, Unit Settings, Prompts, and training random seeds
- F.3 Robustness to Intervention Dimensionality
- Instructions for reporting errors