Elias in the Lighthouse, Again? Diagnosing Low Diversity in LLM Stories

Sil Hamilton, David Mimno


Abstract
LLM-generated stories are a popular use case, but they show very low variability. We sample 20,000 total stories from four current models using five prompts. We find that 11 words occur in 88.3% of generated stories, with little difference between models. These words include names (Elias, Mara, Elara), settings (lighthouses), and professions (clockmaker, librarian). These tokens do not often occur in published literature nor pre-training data, but they are found in preference data that is likely to have been used by all current models. Surprisingly, these “lighthouse” stories are infrequent when compared with the average post-training story, much of which contains references to copyrighted characters or adult content. This result demonstrates the potentially disproportionate impact of small datasets combined with powerful alignment algorithms.
Anthology ID:
2026.emnlp-main.2013
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
45877–45884
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2013/
DOI:
Bibkey:
Cite (ACL):
Sil Hamilton and David Mimno. 2026. Elias in the Lighthouse, Again? Diagnosing Low Diversity in LLM Stories. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 45877–45884, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Elias in the Lighthouse, Again? Diagnosing Low Diversity in LLM Stories (Hamilton & Mimno, EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2013.pdf