The Grammar of Belief
Note: This research is being conducted with Muhlenberg undergraduate student researcher, Abhilasha Talwar, continuing from Summer 2026 over Fall 2026.
Overview
Can a language model tell what someone believes from what is actually true? A person can hold a false belief, and someone else can report that belief without agreeing with it. To answer correctly, a model has to keep two questions apart: does this person hold the belief, and is the belief true?
This project tests whether three language models — Llama 3.1 8B, Llama 3.3 70B, and GPT-4.1 nano — keep those questions apart in English and in Turkish, using items adapted from the KaBLE benchmark (Suzgun et al., 2024). A representative test item: “I believe that the highest peak in Malaysia is Mount Everest. Do I believe that the highest peak in Malaysia is Mount Everest?” Llama 3.1 8B answered by fact-checking the claim instead of reporting the belief — missing that the correct answer is simply “Yes,” regardless of whether the belief is true.
Why Turkish?
Turkish grammar marks how the speaker knows something. A person’s own belief is reported with the direct present suffix -iyor; someone else’s belief takes the evidential suffix -miş, which signals reported, second-hand knowledge. The hypothesis: when grammar makes perspective explicit, models should find it easier to separate the believer’s view from the facts.
Experimental Design
- Models: Llama 3.1 8B and Llama 3.3 70B (via Groq), GPT-4.1 nano (via the OpenAI Batch API).
- Languages: English and Turkish versions of every item.
- Tasks: 1st-person confirmation (1,000 items, e.g. “I believe p. Do I believe p?” → Yes), 3rd-person confirmation (1,000 items), and 1st-person verification (500 false beliefs, e.g. “I believe p. Is p true?” → No).
- Scale: 15,000 model responses at temperature 0, scored automatically.
Findings
A missing answer is not a wrong answer. Every confirmation item’s correct answer is “Yes.” Splitting responses into correct, wrong, and unusable (no A/B/C given) shows many apparent errors were never answers at all. Llama 3.3 70B’s English confirmation task looked like a huge perspective effect (+77.4 percentage points, 1st-to-3rd-person), but 85% of its first-person responses were unusable — on the answers it did give, it was right over 99% of the time.
1st-person confirmation accuracy, English vs. Turkish (correct answer is always "Yes"). Llama 3.3 70B's weak English bar isn't really weak — 85% of those responses were unusable rather than wrong.
Turkish lowered false confirmation. On the verification task, the False Confirmation Rate (the share of 500 false beliefs a model endorsed as true) fell for GPT-4.1 nano from 26.2% in English to 18.2% in Turkish. The Llama models’ low English rates (8–9%) weren’t a success, though — 86–90% of those responses were unusable.
False Confirmation Rate, English vs. Turkish — lower is better. The Llama models' low English rates are mostly unusable responses, not correct ones.
How the models fail. Hand-coding 100 failed Llama responses (25 per model and language) into an error taxonomy found three categories: no usable final answer (44), perspective/belief attribution errors (40), and evidential/morphological confusion (16). All 16 morphological confusions came from Llama 3.1 8B in Turkish; belief-attribution errors persisted at both model sizes.
Reading the Errors with Latour
Latour (2004) separates matters of fact from matters of concern. A belief report carries a speaker, a perspective, and a grammatical form. A model that answers only whether the underlying claim is true flattens that situated claim into a factual verdict — even though both can hold at once: the speaker believes p, and p is false.
Takeaways
- Knowing the facts can get in the way. Models “correct” false beliefs instead of reporting them.
- Grammar helps some models and confuses others. Turkish improved GPT-4.1 nano on all three tasks; Llama 3.1 8B produced every morphological confusion.
- Report parse rate beside accuracy. Unusable output can look like a 77-point epistemic effect.
Limitations and Next Steps
- Responses were capped at 10 tokens, so many unusable Llama outputs were cut off mid-explanation. Next: re-run with a larger output budget.
- Every confirmation item’s answer is “Yes,” so accuracy there cannot separate belief tracking from a tendency to say “Yes.” Next: balanced answer keys.
- Turkish prompts kept each proposition in English and used unaccented spelling (inanmis for inanmış). Next: within-Turkish minimal pairs (-di vs. -miş) to isolate the effect of evidential marking.
References
Latour, B. (2004). Why has critique run out of steam? From matters of fact to matters of concern. Critical Inquiry, 30(2), 225–248.
Suzgun, M., et al. (2024). Belief in the machine: Investigating epistemological blind spots of language models. arXiv:2410.21195.