The One-Word Census: Answer-Choice Conformity Across 44 Language Models

Under no-system-prompt, single-turn conditions, 44 language models exhibit extreme answer convergence on 31 open-ended one-word prompts (e.g., "Name a tree."): for "Pick a word — any word.", 41% output "serendipity"; the study introduces the standardized lightweight evaluation protocol One-Word Census and reveals that while convergence is extreme (one answer occupies >80% of responses in 7/31 categories), conformity varies over fourfold across models—and this variation is structured: persona- and community-tuned models (e.g., Claude-instant-1.2, OpenAssistant, zephyr-7b-beta) are most divergent from the population consensus.
Methodology: The One-Word Census Protocol
- Uses 31 deliberately minimal single-turn prompts, each naming a category with many valid one-word answers (e.g., "Name a tree.", "Name a color.");
- Each model answers each prompt four times, with no system prompt;
- Evaluation uses exact-match on normalized tokens—no embeddings, no human judge;
- Cost ≈ $1 per model; full implementation reported in arXiv:2607.12796v1.
Key Findings
- Convergence is pervasive and extreme: in 7 of 31 categories, a single answer accounts for >80% of all model outputs (e.g., "Pick a word — any word." → "serendipity" at 41%);
- Model-level conformity varies substantially: the answer-choice surprisal (leave-one-out average −log₂ probability of a model’s answers under the pooled distribution of all other models) differs by >4× between highest- and lowest-conformity models;
- Variation is structured: persona-tuned (e.g., Claude-instant-1.2) and community-tuned models (e.g., OpenAssistant, zephyr-7b-beta) deviate most strongly, while base models (e.g., Llama-2-7b-chat, Gemma-2b) and instruction-tuned models (e.g., Mistral-7b-instruct) align more closely with the population.
Methodological Contribution
- Introduces the One-Word Census—a low-cost, highly reproducible, annotation-free behavioral probe for language models;
- Reveals that model output distributions are not uniform samples but reflect structured biases shaped by training data priors and alignment strategies;
- Provides a new axis for interpretability, safety alignment assessment, and community preference modeling: answer-choice surprisal serves as a quantifiable metric of a model’s ‘consensus deviation’.