Unstructured Minds, Predictable Machines: A Comparative Study of Narrative Cohesion in Human and LLM Stream-of-Consciousness Writing

Nellia Dzhubaeva, Katharina Trinley, Laura Pissani


Abstract
This paper examines differences between stream-of-consciousness (SoC) narratives written by humans and those generated by large language models (LLMs) to assess narrative coherence and personality expression. We generated texts by prompting LLMs (Llama-3.1-8B & DeepSeek-R1-Distill-Llama-8B) with the first half of SoC-essays while either providing the models with the personality characteristics (Big Five) or omitting them. Our analysis revealed consistently low similarity between LLM-generated continuations and original human texts, as measured by cosine similarity, perplexity, and BLEU scores. Including explicit personality traits significantly enhanced Llama-3.1-8B’s performance, particularly in BLEU scores.Further analysis of personality expression showed varying alignment patterns between LLMs and human texts. Specifically, Llama-3.1-8B exhibited higher extraversion but low agreeableness, while DeepSeek-R1-Distill-Llama-8B displayed dramatic personality shifts during its reasoning process, especially when prompted with personality traits, with all models consistently showing very low Openness.
Anthology ID:
2025.acl-srw.85
Volume:
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 4: Student Research Workshop)
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Jin Zhao, Mingyang Wang, Zhu Liu
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ACL | WS
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Publisher:
Association for Computational Linguistics
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Pages:
1079–1096
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URL:
https://preview.aclanthology.org/landing_page/2025.acl-srw.85/
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Cite (ACL):
Nellia Dzhubaeva, Katharina Trinley, and Laura Pissani. 2025. Unstructured Minds, Predictable Machines: A Comparative Study of Narrative Cohesion in Human and LLM Stream-of-Consciousness Writing. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 4: Student Research Workshop), pages 1079–1096, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Unstructured Minds, Predictable Machines: A Comparative Study of Narrative Cohesion in Human and LLM Stream-of-Consciousness Writing (Dzhubaeva et al., ACL 2025)
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https://preview.aclanthology.org/landing_page/2025.acl-srw.85.pdf