Source-linked AI summary

Evaluating Character Understanding of Large Language Models via Character Profiling from Fictional Works

Xinfeng Yuan, Siyu Yuan, Yuhan Cui, Tianhe Lin, Xintao Wang, Rui Xu, Jiangjie Chen, Deqing Yang

arXiv:2404.12726v3cs.CL

TL;DR

Earlier character-understanding evaluations focus on classification or characteristic imitation, leaving nuanced understanding through profile generation understudied. This paper introduces the CROSS dataset and evaluates profiles against references and through motivation recognition. The experiments find LLM-generated profiles generally perform well, while still showing errors, especially with complex narratives.

  • Problem

    Prior character-understanding evaluations emphasize classification and characteristic imitation, while character profiling is widely used for role-playing-agent development but remains understudied.

    Source: §1 · p. 1
  • Method

    The paper constructs the literature-expert-sourced CROSS dataset and evaluates generated profiles through reference-based factual consistency and downstream motivation recognition.

    Source: §1 · p. 1, §2 · p. 3, §4.2 · p. 5
  • Results

    LLMs generally perform well at character profiling, but even advanced models sometimes produce hallucinations and errors, particularly with complex narratives.

    Source: §7 · p. 9
  • Takeaways & Limitations

    Motivation Recognition results indicate that each of the four character-profile dimensions matters for recognizing characters’ decision motivations.

    Source: §1 · p. 2

    Evaluation may be biased by possible training exposure to the books, LLM-evaluator errors, and the design of the three tested summarization methods.

    Source: Limitations · p. 9

Abstract

from arXiv · show

Large language models (LLMs) have demonstrated impressive performance and spurred numerous AI applications, in which role-playing agents (RPAs) are particularly popular, especially for fictional characters. The prerequisite for these RPAs lies in the capability of LLMs to understand characters from fictional works. Previous efforts have evaluated this capability via basic classification tasks or characteristic imitation, failing to capture the nuanced character understanding with LLMs. In this paper, we propose evaluating LLMs' character understanding capability via the character profiling task, i.e., summarizing character profiles from corresponding materials, a widely adopted yet understudied practice for RPA development. Specifically, we construct the CroSS dataset from literature experts and assess the generated profiles by comparing them with ground truth references and evaluating their applicability in downstream tasks. Our experiments, which cover various summarization methods and LLMs, have yielded promising results. These results strongly validate the character understanding capability of LLMs. Resources are available at https://github.com/Joanna0123/character_profiling.

1 Introduction

The paper argues that classification and characteristic imitation do not capture nuanced character understanding, and evaluates that understanding through character profiling. It introduces the CROSS dataset and two evaluation tasks, then reports promising results across summarization methods and LLMs.

1 Introduction

  • Character profiling offers a more nuanced generative assessment than prior character classification and characteristic-imitation tasks.The paper frames profile generation as a challenging, understudied practice already used in role-playing-agent development.Source: §1 · p. 1
  • CROSS and two evaluation tasks address the lack of high-quality datasets and protocols for evaluating generated character profiles.The dataset draws on literature experts; evaluation compares profiles with references and tests whether they support motivation recognition.Source: §1 · pp. 1–2
  • Experiments across summarization methods and LLMs find profiles satisfactory but leave room for improvement, with all four profile dimensions important for motivation recognition.The results also suggest possible information loss in role-playing agents built on generated profiles.Source: §1 · p. 2
  • The paper presents an evaluation framework, a literature-expert-sourced dataset, and experiments demonstrating the promise of LLM-based character profiling.These are the stated contributions of the work.Source: §1 · p. 2

2 Related Work

Prior RPA development uses manual construction, online resources, or automatic extraction, while character-understanding research has emphasized classification, prediction, and role-playing. The paper introduces motivation recognition to assess whether profiles support understanding characters’ decisions.

2 Related Work

  • RPA development approaches include manual construction, online resource collection, and automatic extraction using LLMs.The paper explores LLMs’ ability to generate character profiles for RPA construction.Source: §2 · pp. 2–3
  • Prior character-understanding work covers identification, personality prediction, and question answering, but not motivation recognition based on character profiles.The proposed task evaluates whether models identify the motivations behind each character decision.Source: §2 · p. 3
  • Character motivation reflects personality and surroundings, linking decisions in narratives to a character’s inner traits and external relationships.The paper uses this connection to motivate assessing decision motivations from profiles.Source: §2 · p. 3

3 Character Profiling Framework

The framework treats character profiling as generating a profile from a character name and a fictional work, organized around four dimensions. It evaluates long-book processing through segmented summarization methods and full-book input where context windows permit.

3.1 Task Formulation

  • Given a character name and fictional work, the model generates a profile covering core character information.The profile is represented through attributes, relationships, events, and personality.Source: §3.1 · p. 3, §3.2 · p. 3

3.2 Character Profile Dimensions

  • The four profile dimensions are attributes, relationships, events, and personality, with events ordered chronologically even when narratives use complex timelines.Attributes include background, skills, talents, objectives, and gender; relationships connect to experiences and personality.Source: §3.2 · p. 3

3.3 Summarization Methods

  • Long-book processing compares hierarchical merging, incremental updating, and one-go summarization, with the latter used for books under 120,000 tokens.Hierarchical merging combines segment summaries iteratively; incremental updating carries prior context forward, addressing the risk that context-free segment summaries may misinterpret later material.Source: §3.3 · pp. 3–4, Figure 2 · p. 4

4 Evaluation Protocol

The protocol evaluates profile generation both against reference profiles and through downstream motivation recognition, using expert-derived material and questions from CROSS.

4.1 Evaluation Tasks

  • Factual consistency examination compares four-section generated profiles with reference profiles, while Motivation Recognition tests whether profiles help models identify decision motivations.Source: §4.1 · pp. 4–5

4.2 Evaluation Metrics

  • Consistency Score uses Llama-3-70B to rate factual alignment from 1–5; Motivation Recognition is measured by dataset-wide accuracy.Source: §4.2 · p. 5

4.3 CROSS Dataset Construction

  • The dataset uses 126 novels published in 2022 and 2023, focuses on each main character, and limits one-go books to fewer than 120,000 tokens.Source: §4.3 · p. 5
  • CROSS draws on expert SuperSummary summaries and analyses, reorganized by GPT-4 into four dimensions and checked by two annotators for information integrity.Source: §4.3 · p. 5
  • GPT-4 generated 641 motivation questions across 126 characters with structurally similar alternative motivations; annotators retained 445 of 641 questions.Source: §4.3 · p. 6

5 Experiment Settings

The experiments compare multiple LLMs and summarization methods under fixed generation settings, then evaluate motivation recognition and profile-dimension ablations.

  • Incremental and hierarchical summarization tested nine LLMs with 3,000-token chunks and profiles capped at 1,200 words; one-go used GPT-4-Turbo and Claude-3-Sonnet.All models used temperature 0 and their original instruction formats.Source: §5 · p. 7
  • Motivation Recognition used GPT-4-Turbo-0409; two annotators also answered all questions to establish human accuracy and standard deviation.Source: §5 · p. 7
  • Dimension ablations used incremental GPT-4 profiles, with each experiment repeated three times and mean and standard deviation reported.Source: §5 · pp. 7–8

6 Experiment Results

Motivation Recognition tests whether profiles support character decisions, while profile-generation experiments compare models and summarization methods. Profiles generally perform promisingly, but event information and complex narratives remain challenging.

6.1 Can LLMs generate character profiles from fictional works precisely?

  • GPT-4 consistently outperforms other models across summarization methods, while larger models such as Qwen1.5-72B-Chat tend to score higher in consistency.Across dimensions, models generally capture personality more consistently than events.Source: §6.1 · p. 8
  • Profiles from summarizing-in-one-go achieve the highest consistency scores in every dimension, surpassing methods that process book content in segments.The authors attribute this to preserving narrative coherence and reducing information loss by processing the whole book at once.Source: §6.1 · p. 8
  • Incremental updating slightly trails hierarchical summarizing in average consistency but performs better for events.Its iterative passes allow the model to revise its understanding as more information arrives or errors are corrected; this accords with Chang et al. (2023), who report greater detail in incremental book summaries.Source: §6.1 · p. 8
  • Case analysis identifies five profile errors: character and relationship misidentification, key-information omission, event misinterpretation, and character misinterpretation.The event category includes failures to revise earlier interpretations after later revelations.Source: §6.1 · p. 8
  • Complex narrative structures can confuse models: shifting perspectives lead to Benjamin Rask/Andrew Bevel trait confusion, while a plot twist in The Housemaid’s Secret yields an incorrect final summary.The examples appear in the character-misidentification and event-misinterpretation cases.Source: §6.1 · p. 8

6.2 Can LLMs recognize the character’s motivation for a specific decision?

  • Consistency scores strongly positively correlate with Motivation Recognition accuracy, supporting the validity of profiling and the link between accurate profiles and motivation understanding.The authors interpret this relationship as evidence that accurate profiles help models understand motivations behind character behavior.Source: §6.2 · p. 9
  • Ablations show all four profile dimensions contribute to Motivation Recognition, with removing events alone lowering accuracy by 9.21%.The authors say events supply plot context for decisions and integrate information from other dimensions; reducing profile information also correlates with greater outcome variance.Source: §6.2 · p. 9

7 Conclusion

The paper introduces an evaluation task for LLM character profiling and applies it to 126 novel character profiles. Its evaluations find generally good performance alongside occasional errors, especially with complex narratives.

7 Conclusion

  • The paper introduces a character-profiling evaluation task using 126 character profiles from novels and evaluates factual consistency and motivation recognition.Source: §7 · p. 9
  • LLMs generally perform well, but even advanced models sometimes hallucinate or err, particularly on complex narratives.The authors identify a need for further improvement.Source: §7 · p. 9

Limitations

The evaluation covers four common profile dimensions, leaving other potential dimensions unexplored. Potential evaluation biases and limitations in the tested summarization methods also constrain the study.

Limitations

  • The study evaluates only four common profile dimensions, leaving other possible dimensions and their downstream effects outside its scope.The authors identify broader dimensions as a direction for future work.Source: Limitations · p. 9
  • Evaluation may be biased if models encountered the selected books during training or if evaluator-LLM errors distort profile-consistency estimates.The authors also note that the three tested summarization methods could be improved.Source: Limitations · p. 9

Ethics Statement

The paper describes annotation safeguards and data-quality risks, while related work covers character dimensions individually and lacks systematic assessment of multidimensional summaries.

Ethics Statement

  • Annotators were paid above the local minimum wage, their privacy was respected, and they consented to research use of processed data.The institution recruited annotators for motivation-recognition dataset construction.Source: Ethics Statement · p. 9
  • The authors cannot guarantee publicly sourced CROSS data are free of harmful or toxic language, and motivation-recognition data quality judgments may vary across people.The latter quality evaluation is based on common sense.Source: Ethics Statement · p. 9

A.1 Dimension

  • Character-summary studies often target a single dimension, while multidimensional RPA summaries lack systematic quality assessment.The cited dimensions include role, relationships, personality, and mental states; multidimensional summaries include attributes, appearance, relationships, and storyline.Source: §A.1 · p. 12

A.2 Evaluation

The evaluation framework covers multiple character-information dimensions, including mental and factual information. Profiles may support downstream applications, though a total word limit can make some dimensions less detailed.

A.2 Evaluation

  • The framework covers character information across dimensions, including objectives, emotions, beliefs, relationships, and interactions with the external world.Objectives reflect desires and intentions, while emotions and beliefs can emerge through reactions and behavior in event profiles.Source: §A.2 · p. 12

A.3 Application

  • Profiles may provide information for fictional-character chatbots, interactive narratives, and study guides, but the total word limit can leave some dimensions less detailed.The profiles may be less detailed on some dimensions than summaries devoted solely to those dimensions.Source: §A.3 · p. 12

B.1 Dataset Construction

  • The dataset comprises 126 fictional novels, selected from 2022–2023 publications and excluding biographical novels and works based on real historical figures.The selection also excludes sequels unless they can be regarded as independent works.Source: §B.1 · p. 12
  • Experts’ SuperSummary book summaries and character analyses were used with developer permission, and only reorganized profiles are released to protect copyright.The materials are used for academic research purposes.Source: §B.1 · p. 12

B.2 Integrity Verification of CROSS dataset

Integrity checks find similar consistency scores across publication years and sales-volume groups, but higher scores for classic works; recent-book scores show no significant year correlation. The appendix also describes summarization methods and reference-profile checks.

B.2 Integrity Verification of CROSS dataset

  • 3.60 vs 3.62 average consistency scores for 2022- and 2023-published books, and 3.58 vs 3.62 for best-selling and other books, are described as very close.The authors conclude that publication year and sales volume do not significantly affect task performance within CROSS.Source: §B.2 · pp. 12–13, Table 5 · p. 13, Table 6 · p. 13
  • Consistency scores are much higher on ten top-rated 20th-century classics than on CROSS, which the authors say suggests their selection reduces data-leakage impact.They attribute the classic-book performance to accumulated related training corpora, including literary analyses and fan creations.Source: §B.2 · p. 13, Table 7 · p. 14
  • −0.037 Spearman correlation (p = 0.799) indicates no significant association between publication year and average consistency across 50 books from the past ten years.The authors infer that prior exposure to some recent books is insufficient for strong performance based on memory alone.Source: §B.2 · p. 13, Figure 3 · p. 14
  • The authors speculate CROSS will remain effective for updated LLMs for at least the next few years and describe a framework for continually expanding it.They state they will keep updating the dataset and evaluating new LLMs.Source: §B.2 · p. 13

C.1 Incremental Updating

  • Incremental updating processes book chunks sequentially, repeatedly incorporating each new chunk into the running summary and compressing it when it exceeds the maximum length.The chunk size is 3,000 tokens and the maximum summary length is 1,200.Source: C Detailed Information of… · p. 13, §C.1 · p. 13

C.2 Hierarchical Merging

  • Hierarchical merging first summarizes chunks separately, then repeatedly merges summaries in context-window-limited groups until a final summary is produced.Subsequent merges may use the prior level-2 summary as context.Source: §C.2 · pp. 13–14

C.3 Summarizing in One Go

  • Summarizing in one go provides the whole book to the model and generates the final summary at once, when the book and prompt fit the context window.This condition is stated for GPT-4 and Claude-3-Sonnet.Source: §C.3 · p. 14

D.1 Reference Profile Examination

  • Two annotators found no plot inconsistencies or misjudgments of character traits in any CROSS reference profile they checked.They compared GPT-4-reorganized profiles with the original plot summaries and character analyses.Source: §D.1 · p. 14

D.2 Manual Evaluation of FCE

Human ratings correlate with Llama-3-70B’s factual-consistency evaluations, and the appendix reports filtering criteria for motivation questions and patterns from traditional metrics. It also notes a long-context prompting issue for Claude-3-Sonnet.

D.2 Manual Evaluation of FCE

  • 0.752 Pearson correlation (p = 4.3e−12) between average human and Llama-3-70B consistency scores is reported as evidence of comparable evaluation ability.The comparison uses 50 sampled profiles and the same scoring prompt for people and the model.Source: §D.2 · p. 14

D.3 Motivation Recognition MCQs filtering

  • 445 motivation-recognition questions remained after filtering, with Fleiss’s κ = 0.91; annotators checked decision-maker, motivation focus, story significance, and leakage criteria.Options were rearranged to distribute correct answers fairly.Source: §D.3 · p. 15

E Traditional Metrics on Generated Profiles

  • Traditional metrics broadly match consistency-score patterns: larger, more complex LLMs perform better, event profiles often score lowest, and one-go summarization outranks hierarchical and incremental methods.Relative model performance varies by metric because ROUGE-L and BLEU emphasize lexical matching, BERTScore semantic similarity, and consistency score factual accuracy.Source: E Traditional Metrics on Generated… · p. 15

F.1 Summarizing in One Go

  • Claude-3-Sonnet sometimes forgets the requested four-section format when the prompt precedes novel content, so the prompt is placed after the content.The authors attribute this behavior to limitations in the model’s long-context capabilities.Source: §F.1 · pp. 15–16
Loading 2404.12726v3…