Humans lead storytelling while AI models mainly expand narratives
Humans Introduce, Models Elaborate: Asymmetric Narrative Agency in Human-LLM Co-Writing
Human-Computer Interaction
Summary
When people and AI language models write stories together, humans tend to create new ideas and story elements. Meanwhile, AI models usually add details and make the story flow better based on what the humans have introduced. This means the AI doesn't simply co-author like a human but acts more like a helper that shapes and expands the human's original story ideas. The study compared human-only, AI-only, and mixed teams to discover this pattern.
What this means in practice
- •For creative writing teams: Improve collaboration tools by designing AI that expands and refines human story ideas instead of generating original plots alone.
- •For content marketing teams: Use AI to elaborate and stabilize narratives initiated by humans for more consistent and engaging marketing content.
Authors
Halfdan Nordahl Fundal, Yuri Bizzoni, Charlotte Gjørup Bilde, Ida Bække Johannesen, Rebekah Baglini
Abstract
Human-LLM co-writing is increasingly used for open-ended text generation, but much prior work focuses on final outputs rather than the interactional dynamics through which stories are produced. We study turn-based collaborative storytelling across three matched conditions: Human-Human (HH), Human-LLM (HA), and LLM-LLM (AA). Using a shared storytelling paradigm, we measure how agents align, introduce novel material, and influence narrative development through turn-level measures of valence adaptation, semantic novelty, transience, and resonance. Our results show that HA co-writing is not intermediate between HH and AA collaboration. Instead, it displays a distinctive asymmetry where humans tend to introduce more novel and persistent narrative material, while LLMs tend to elaborate and stabilize the existing context. These findings suggest that, in this setting, LLMs function less as human co-authors and more as adaptive narrative amplifiers that reshape how agency is distributed in collaborative writing.