Evaluating LLM Story Generation through Large-scale Network Analysis of Social Structures
Hiroshi Nonaka, K. E. Perry
TL;DR
Problem: scalable evaluation of LLM storytelling is difficult with human judgments. Approach: build signed character networks from narrative co-occurrences in over 1,200 stories (LLMs and humans), and analyze density, clustering, and edge polarity, including positive/negative subgraphs and Wasserstein distances. Key findings: LLM-generated stories exhibit higher density and clustering and a positivity bias relative to human-written stories, consistent with prior human assessments. Significance: the network-based analysis provides a scalable, quantitative tool for assessing LLM creativity and can be extended to other genres, longer texts, and interactive narratives.
Abstract
Evaluating the creative capabilities of large language models (LLMs) in complex tasks often requires human assessments that are difficult to scale. We introduce a novel, scalable methodology for evaluating LLM story generation by analyzing underlying social structures in narratives as signed character networks. To demonstrate its effectiveness, we conduct a large-scale comparative analysis using networks from over 1,200 stories, generated by four leading LLMs (GPT-4o, GPT-4o mini, Gemini 1.5 Pro, and Gemini 1.5 Flash) and a human-written corpus. Our findings, based on network properties like density, clustering, and signed edge weights, show that LLM-generated stories consistently exhibit a strong bias toward tightly-knit, positive relationships, which aligns with findings from prior research using human assessment. Our proposed approach provides a valuable tool for evaluating limitations and tendencies in the creative storytelling of current and future LLMs.
