How LLMs Build Fictional Worlds: Setting and Narrative Space in AI-Generated Creative Storytelling

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The gist

The paper investigates the complex mechanisms by which Large Language Models (LLMs) construct and manage fictional worlds, focusing specifically on the deployment of setting and narrative space

In short

The episode discusses a paper analyzing how LLMs build fictional worlds compared to human authors. The study found that LLMs systematically overproduce 'perceived space' or atmosphere, while underproducing 'action space' or physical interaction. This suggests AI narrative construction is fundamentally different from traditional human fiction, requiring guidance toward embodied interaction.

Key concepts

Perceived Space
This is the tendency of LLMs to prioritize atmosphere or mood in their generated text. The study found that LLMs significantly overproduce this element compared to human writers, often reaching a normalized frequency twice the human baseline.
Action Space
This refers to the physical interaction and movement within a story's setting, which human authors typically ground their characters in. The analysis showed LLM-generated texts underproduce this concrete action space compared to human benchmarks.
Space-Conditioned Generation
This is a suggested method for prompting AI to make spatial elements more intentional during the generation process. It aims to allow for more controlled and deliberate worldbuilding beyond relying solely on existing training data.

Terminology used across episodes

This episode discusses

The paper

How LLMs Build Fictional Worlds: Setting and Narrative Space in AI-Generated Creative Storytelling · Read on arXiv

Katrin Rohrbacher, Björn Nieth, Emmanuelle Salin, Bjoern Eskofier, Michaela Mahlberg

The Text and Language Lab, Department of Digital Humanities and Social Studies, Friedrich-Alexander University (FAU) Erlangen-Nürnberg · Department of Artificial Intelligence in Biomedical Engineering (AIBE), Friedrich-Alexander University (FAU) Erlangen-Nürnberg · Chair of AI-supported Therapy Decisions, Ludwig Maximilian University (LMU) Munich · Department of Linguistics and Communication, University of Birmingham · Munich Center for Machine Learning (MCML) · Institute of AI for Health, Helmholtz Centre Munich

In this paper, we analyze how Large Language Models (LLMs) employ worldbuilding strategies, focusing on setting as one measurable dimension of storyworld construction. We compare 1,000 AI-generated stories per model in English and German with human-authored fiction from Project Gutenberg. Building on prior work, we operationalize setting through five types of narrative space: "action", "perceived," "visual," "descriptive" and "no space", identified using fine-tuned BERT classifiers for German and English. We generate narratives using GPT 4.1, LlaMA 3.3, Mistral 3.2, and Gemma 3 and compare their spatial distributions to a human-authored baseline. We find that human-authored texts predominantly employ "action space," grounding narratives in embodied character-environment interaction, whereas LLMs systematically overproduce "perceived space," emphasizing atmosphere and affect. This divergence remains stable across narrative time. Overall, our findings show that LLMs exhibit worldbuilding patterns that differ consistently from human-authored fiction in ways that are both model-specific and language-sensitive.

Transcript

Introduction to the show: ident: AI Radio. Generated commentary on the latest Artificial Intelligence papers.

Tom: Next we'll be talking about the paper "How LLMs Build Fictional Worlds: Setting and Narrative Space in AI-Generated Creative Storytelling".

Jane: The paper was written by Katrin Rohrbacher, Björn Nieth, Emmanuelle Salin, Bjoern Eskofier and Michaela Mahlberg from The Text and Language Lab, Department of Digital Humanities and Social Studies, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Department of Artificial Intelligence in Biomedical Engineering (AIBE), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Chair of AI-supported Therapy Decisions, Ludwig Maximilian University (LMU) Munich and Department of Linguistics and Communication, University of Birmingham and Munich Center for Machine Learning (MCML) and Institute of AI for Health, Helmholtz Centre Munich.

Tom: Stay tuned as we take you through the paper and discuss its implications.

Title: Jane: So, let's talk about the title again and what it implies for its scope. The paper is "How LLMs Build Fictional Worlds: Setting and Narrative Space in AI-Generated Creative Storytelling," and it sets up a very specific investigative goal: to measure setting as one of the primary mechanisms of worldbuilding.

Tom: And the implications are massive because, if the AI isn't building worlds like humans do, what we might think is just a stylistic variation could actually be something much deeper about how AI thinks about space and narrative flow.

Lu: It’s not just a surface-level difference; it’s an internal difference in how LLMs prioritize different elements of the environment. The way they structure the storyworld seems fundamentally different from its human counterpart, which is what makes this title so provocative.

Meng: I think the initial comparison between this AI generation and Project Gutenberg texts is very practical for us because it provides a clear historical baseline to measure against, allowing us to see if these models are just reproducing old styles or if they’ are generating something new.

Lalam: This difference suggests that the way we perceive AI-generated content might change over time because its narrative construction is inherently different from our traditional understanding of human fiction.

Tom: It's a strong contrast to be able to measure so clear a distinction, and that sets the stage for seeing exactly where those differences are in the next segment.

Summary: Jane: The paper’s summary shows us the core finding: that LLMs systematically overproduce "perceived space" compared to human authors. This isn't just a tiny difference, which is quite striking given how much we usually rely on a baseline for AI performance.

Tom: We’re seeing that when the human authors use action space—movement and physical interaction—the characters are grounded in their environment, but the LLM-generated texts tend to emphasize atmosphere and feeling instead of concrete action.

Lu: The data is quite specific about this too; for instance, looking at the opening fifteen sentences in Figure two GPT four point one reaches a normalized frequency around zero point four seven in English, which is roughly twice the human baseline—that's a huge overproduction of atmosphere!

Meng: And it’s important to note that this isn't just limited to the opening sentence; the authors show us that this bias persists across narrative time, meaning the AI’s preference for mood is consistent throughout a long story.

Lalam: This means that when we think about cultural impact, LLMs are creating worlds that feel more like a sustained mood rather than a sequence of events, and that’s a significant shift in the narrative experience we are seeing.

Tom: It’s fascinating how the models prioritize ambiance over concrete action, and it really shows us where this bias is rooted in the data.

Jane: We've seen that specific pattern, but now let's look at how they measure this bias across time and space as we move into our next segment.

Improvements: Tom: Now, we’ve established that LLMs tend to overproduce perceived space and underproduce action space compared to human authors. The question is, what does the paper suggest we can do with this knowledge?

Jane: One key area of study is why this happens, which the analysis helps us understand by looking at things like prompt sensitivity. We find that while prompt phrasing matters, the overall spatial trends are quite robust across various versions of the instruction set.

Lu: That's a confidence boost for our data analysis, but it also highlights a challenge; even if we tweak the prompts, we’ aren't fixing the fundamental tendency of producing atmosphere over action. We still have to address that core bias in how they build worlds.

Meng: The authors suggest looking at "space-conditioned generation," which is a way to make space more intentional during prompting. This could potentially allow for much more controlled and deliberate worldbuilding, moving beyond the existing patterns of reliance on just the training data.

Lalam: I think the paper’s most important suggestion is that we need to guide the AI not just to learn from a baseline, but also to understand human preference for embodied interaction, which is what action space really represents.

Tom: That’s a huge idea, Lalam—forcing the AI to act like a novelist by requiring it to utilize action space in its generation is a powerful constraint.

Jane: We've covered the findings and the practical solutions, so let's bring all these insights together in our final summary of this paper.

Conclusion: Tom: So, wrapping up our discussion on "How LLMs Build Fictional Worlds: Setting and Narrative Space in AI-Generated Creative Storytelling," we have a very clear picture of the systematic differences between human and machine fiction. We’ve seen that LLMs strongly overrepresent perceived space while underproducing action space.

Jane: It really shows that these models aren't just mimicking style; they are constructing story worlds in a way that is fundamentally different from literary norms, which is a huge insight into the capabilities of AI.

Lu: The fact that this pattern holds across models and languages means we’ve found a consistent stylistic marker for AI-generated fiction, which opens up massive possibilities for understanding authorship.

Meng: And it gives us a benchmark—a way to measure how far our generative systems are from achieving that human level of grounded action and narrative momentum.

Lalam: We must remember the full implications of this paper and use its framework to guide the development so that AI can eventually achieve both atmospheric resonance and physical grounding.

Tom: It’s a really rich area of research, especially when we look at how these spatial metrics offer a path toward richer evaluation of AI-generated narratives.

Jane: It’s definitely going to be interesting to see what the next study on this topic reveals. Thank you all for joining us today and with that the final thoughts on "How LLMs Build Fictional Worlds: Setting and Narrative Space in AI-Generated Creative Storytelling."

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