@inproceedings{han-etal-2022-go,
    title = "Go Back in Time: Generating Flashbacks in Stories with Event Temporal Prompts",
    author = "Han, Rujun  and
      Chen, Hong  and
      Tian, Yufei  and
      Peng, Nanyun",
    editor = "Carpuat, Marine  and
      de Marneffe, Marie-Catherine  and
      Meza Ruiz, Ivan Vladimir",
    booktitle = "Proceedings of the 2022 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies",
    month = jul,
    year = "2022",
    address = "Seattle, United States",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/ingest-nlpsi/2022.naacl-main.104/",
    doi = "10.18653/v1/2022.naacl-main.104",
    pages = "1450--1470",
    abstract = "Stories or narratives are comprised of a sequence of events. To compose interesting stories, professional writers often leverage a creative writing technique called \textit{flashback} that inserts past events into current storylines as we commonly observe in novels and plays. However, it is challenging for machines to generate \textit{flashback} as it requires a solid understanding of event \textbf{temporal order} (e.g. \textit{feeling hungry} before \textit{eat}, not vice versa), and the creativity to arrange storylines so that earlier events do not always appear first in \textbf{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 \textit{flashbacks}. We propose to address these issues using structured storylines to encode events and their pair-wise temporal relations (before, after and vague) as \textbf{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 \textit{flashbacks} while maintaining textual diversity, fluency, and temporal coherence."
}