Source-linked AI summary

Telling Stories through Multi-User Dialogue by Modeling Character Relations

Wai Man Si, Prithviraj Ammanabrolu, Mark O. Riedl

arXiv:2105.15054v1cs.CLcs.AI

TL;DR

Character-driven story continuation requires models to preserve personas and relationships while advancing a narrative. The paper extends CRD3 with automatically extracted character information and trains a multi-task model for character prediction and story continuation. Ablations show that relationship-aware multi-task training improves story continuation accuracy, while the dataset’s fantasy role-playing context introduces bias and scope limitations.

  • Problem

    Character-driven continuation must preserve personas and relationships while following and advancing the story.

    Source: §1 · p. 1
  • Method

    The paper extends CRD3 with automatically extracted personas and pairwise relationships, then jointly trains next-character prediction and story continuation.

    Source: §1 · p. 2, §3.2 · p. 3
  • Results

    Relationship-aware multi-task training improves story continuation accuracy over the evaluated alternatives.

    Source: §1 · p. 2, §4.2 · pp. 4–5, §5 · p. 5
  • Takeaways & Limitations

    Multi-task training on dialogue and automatically extracted relationship information is an effective way to support character-driven story continuation.

    Source: §5 · p. 5

    Training on fantasy role-playing data may reproduce biases, including non-normative language that may be inappropriate in the real world.

    Source: §6 · p. 5

Abstract

from arXiv · show

This paper explores character-driven story continuation, in which the story emerges through characters' first- and second-person narration as well as dialogue -- requiring models to select language that is consistent with a character's persona and their relationships with other characters while following and advancing the story. We hypothesize that a multi-task model that trains on character dialogue plus character relationship information improves transformer-based story continuation. To this end, we extend the Critical Role Dungeons and Dragons Dataset (Rameshkumar and Bailey, 2020) -- consisting of dialogue transcripts of people collaboratively telling a story while playing the role-playing game Dungeons and Dragons -- with automatically extracted relationships between each pair of interacting characters as well as their personas. A series of ablations lend evidence to our hypothesis, showing that our multi-task model using character relationships improves story continuation accuracy over strong baselines.

1 Introduction

The paper frames character-driven story continuation as selecting dialogue and narration that preserve personas and relationships while advancing the plot. It extends CRD3 and uses multi-task learning to improve continuation accuracy.

  • Character-driven continuation must maintain persona consistency, track relationships, and logically advance the story while generating character interactions.Source: §1 · p. 1
  • The task predicts the next character response using dialogue-only continuation over collaborative Dungeons and Dragons narratives.Source: §1 · pp. 1–2
  • The extended CRD3 dataset adds automatically extracted character personas and pairwise relationship types from Critical Role Wiki descriptions.Source: §1 · p. 2
  • Training jointly on character-related sub-tasks significantly improves story continuation accuracy.Source: §1 · p. 2
  • The primary contributions are the extended CRD3 methodology and a multi-task system leveraging character relations and persona information.Source: §1 · p. 2

2 Related Work and Background

Prior storytelling systems emphasize plot coherence or sequential plot generation, while dialogue systems model personas and interactions without requiring long-term story continuation. This paper sits at the intersection of these limitations.

  • Symbolic storytelling systems enforce plot coherence through explicit rules, whereas neural systems generally learn plot-driven generation from story corpora.Source: §2 · p. 2
  • Modern plot-generation pipelines often generate a high-level plot before filling in the story under plot constraints.Source: §2 · p. 2
  • Existing storytelling tasks generally omit dialogue and character interactions, including Story Cloze’s prediction of a story ending.Source: §2 · p. 2
  • Persona-focused dialogue systems model agent consistency and contextual information but typically lack story or plot and use less long-term context.Source: §2 · p. 2

3 Character-Driven Storytelling

The paper extends CRD3 with character relationships and uses a shared-transformer multi-task architecture for next-character prediction and story continuation. The model combines historical summaries, relationship labels, and recent interactions as context.

3.1 CRD3 Automated Dataset Extension

  • CRD3 contains 159 episodes, 398,682 turns, and 34,243 human-written summary dialogue chunks spanning dialogue and first- and second-person narration.Source: §3.1 · pp. 2–3
  • The dataset extension clusters Critical Role Wiki relation descriptions with TF-IDF and K-means, then assigns positive, negative, or neutral labels to dialogue chunks.Source: §3.1 · p. 3

3.2 Multi-task Learning

  • The multi-task model predicts both the next character and the next story response from summaries, pairwise relationship labels, and the last n interaction turns.Source: §3.2 · p. 3
  • The architecture uses separate task-specific output layers over shared pre-trained transformer blocks.Source: Figure 1 · p. 3, §3.2 · p. 3
  • Joint training combines ranking and classification losses, sharing network parameters between response retrieval and next-character prediction.Source: §3.2 · p. 3

4 Evaluation

The evaluation tests historical context requirements and whether relation information plus multi-task training improves character prediction and story continuation. Results show that long context is important, while multi-task relation-aware models perform best for story continuation.

4 Evaluation

  • The base evaluation model is a BERT-like bi-encoder ranker, and the experiments use the architecture described for jointly modeling the two subtasks.The reported ablations build on this transformer ranker.Source: §4 · p. 3
  • The evaluation varies prior summary chunks and compares base versus relation-enriched inputs under single-task and joint multi-task training.Story continuation uses Hits@N, while character prediction uses frequency-weighted F1.Source: §4.1 · p. 4, §4.2 · p. 4, §4 · p. 4

4.1 Historical Context Ablations

  • Performance continues increasing with added historical context through the maximum tested length of 10, indicating that CRD3 requires unusually long contexts.The largest average gain occurs when increasing context from one chunk to two, with smaller gains from additional chunks.Source: §4.1 · p. 4, Table 4 · p. 4

4.2 Multi-task Ablations

  • The relation labels remain fixed across the entire story, effectively averaging relationship changes over time.More fine-grained time-varying labels might perform better but would require extensive additional human annotation.Source: §4.2 · p. 4
  • For story continuation, the Base+Summary+Relations multi-task model outperforms all other tested models, while multi-task models consistently beat their single-task counterparts.The authors attribute the improvement to combining relationship-cluster inputs with next-character prediction, supporting more accurate persona-consistent continuation.Source: §4.2 · pp. 4–5
  • Character prediction is strongest for Base+Summary multi-task and Base+Relations single-task models, closely matching Base+Summary+Relations multi-task performance.Thus, the relation-aware multi-task configuration is most clearly advantageous for story continuation rather than character prediction.Source: §4.2 · p. 4

5 Conclusions

The paper hypothesizes that character relationships improve character-driven story completion and evaluates this through ablations. The results support multi-task training on dialogue and automatically extracted relationship information as an efficient approach.

  • Ablation studies support the hypothesis that relationship information improves character-driven story completion.Source: §5 · p. 5
  • Multi-task training on character dialogue and automatically extracted relationship information is identified as a particularly efficient way to provide this information.Source: §5 · p. 5

6 Broader Impacts

The work discusses implications for natural-language learning agents that must maintain a consistent persona, while noting bias risks from its role-playing-game data and retrieval-based mitigation.

  • Character-driven storytelling may inform learning agents that communicate naturally while maintaining a consistent character or persona.Source: §6 · p. 5
  • Because the system learns from fantasy role-playing interactions, it may reproduce data biases, including non-normative language; retrieval mitigates but does not eliminate some risks.Source: §6 · p. 5

A.1 CRD3 Extended Examples

Tables 5 and 6 present randomly selected CRD3 extended examples.

A.2 Experiment parameter details

The multi-task model uses hyperparameters adapted from Urbanek et al. (2019) without further tuning, with experiments run on four Nvidia TitanX GPUs in under 24 hours.

  • The multi-task model’s hyperparameters were adapted from Urbanek et al. (2019) and not tuned further.Source: Table 7 · p. 8
  • All experiments were conducted on 4 Nvidia TitanX GPUs.Source: Table 7 · p. 8
  • The experiments take less than 24 hours.Source: Table 7 · p. 8

A.3 Clustering Examples

Table 8 presents pair-wise character relationship information generated using clustering and VADER.

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