Go Back in Time: Generating Flashbacks in Stories with Event Temporal Prompts

Rujun Han, Hong Chen, Yufei Tian, Nanyun Peng


Abstract
Stories or narratives are comprised of a sequence of events. To compose interesting stories, professional writers often leverage a creative writing technique called *flashback* that inserts past events into current storylines as we commonly observe in novels and plays. However, it is challenging for machines to generate *flashback* as it requires a solid understanding of event **temporal order** (e.g. *feeling hungry* before *eat*, not vice versa), and the creativity to arrange storylines so that earlier events do not always appear first in **narrative order**. Two major issues in existing systems that exacerbate the challenges: 1) temporal bias in pertaining and story datasets that leads to monotonic event temporal orders; 2) lack of explicit guidance that helps machines decide where to insert *flashbacks*. We propose to address these issues using structured storylines to encode events and their pair-wise temporal relations (before, after and vague) as **temporal prompts** that guide how stories should unfold temporally. We leverage a Plan-and-Write framework enhanced by reinforcement learning to generate storylines and stories end-to-end. Evaluation results show that the proposed method can generate more interesting stories with *flashbacks* while maintaining textual diversity, fluency, and temporal coherence.
Anthology ID:
2022.naacl-main.104
Volume:
Proceedings of the 2022 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies
Month:
July
Year:
2022
Address:
Seattle, United States
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1450–1470
Language:
URL:
https://aclanthology.org/2022.naacl-main.104
DOI:
10.18653/v1/2022.naacl-main.104
Bibkey:
Cite (ACL):
Rujun Han, Hong Chen, Yufei Tian, and Nanyun Peng. 2022. Go Back in Time: Generating Flashbacks in Stories with Event Temporal Prompts. In Proceedings of the 2022 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 1450–1470, Seattle, United States. Association for Computational Linguistics.
Cite (Informal):
Go Back in Time: Generating Flashbacks in Stories with Event Temporal Prompts (Han et al., NAACL 2022)
Copy Citation:
PDF:
https://aclanthology.org/2022.naacl-main.104.pdf
Software:
 2022.naacl-main.104.software.zip
Code
 pluslabnlp/flashback_gen
Data
BookCorpusROCStoriesWritingPrompts