What do Large Language Models Learn about Scripts?

Abhilasha Sancheti, Rachel Rudinger


Abstract
Script Knowledge (Schank and Abelson, 1975) has long been recognized as crucial for language understanding as it can help in filling in unstated information in a narrative. However, such knowledge is expensive to produce manually and difficult to induce from text due to reporting bias (Gordon and Van Durme, 2013). In this work, we are interested in the scientific question of whether explicit script knowledge is present and accessible through pre-trained generative language models (LMs). To this end, we introduce the task of generating full event sequence descriptions (ESDs) given a scenario as a natural language prompt. Through zero-shot probing, we find that generative LMs produce poor ESDs with mostly omitted, irrelevant, repeated or misordered events. To address this, we propose a pipeline-based script induction framework (SIF) which can generate good quality ESDs for unseen scenarios (e.g., bake a cake). SIF is a two-staged framework that fine-tunes LM on a small set of ESD examples in the first stage. In the second stage, ESD generated for an unseen scenario is post-processed using RoBERTa-based models to filter irrelevant events, remove repetitions, and reorder the temporally misordered events. Through automatic and manual evaluations, we demonstrate that SIF yields substantial improvements (1-3 BLEU points) over a fine-tuned LM. However, manual analysis shows that there is great room for improvement, offering a new research direction for inducing script knowledge.
Anthology ID:
2022.starsem-1.1
Volume:
Proceedings of the 11th Joint Conference on Lexical and Computational Semantics
Month:
July
Year:
2022
Address:
Seattle, Washington
Venues:
*SEM | NAACL
SIG:
SIGSEM
Publisher:
Association for Computational Linguistics
Note:
Pages:
1–11
Language:
URL:
https://aclanthology.org/2022.starsem-1.1
DOI:
10.18653/v1/2022.starsem-1.1
Bibkey:
Cite (ACL):
Abhilasha Sancheti and Rachel Rudinger. 2022. What do Large Language Models Learn about Scripts?. In Proceedings of the 11th Joint Conference on Lexical and Computational Semantics, pages 1–11, Seattle, Washington. Association for Computational Linguistics.
Cite (Informal):
What do Large Language Models Learn about Scripts? (Sancheti & Rudinger, *SEM 2022)
Copy Citation:
PDF:
https://aclanthology.org/2022.starsem-1.1.pdf
Code
 abhilashasancheti/script-generation