Are LLMs classical or nonmonotonic reasoners? Lessons from generics

Alina Leidinger, Robert Van Rooij, Ekaterina Shutova


Abstract
Recent scholarship on reasoning in LLMs has supplied evidence of impressive performance and flexible adaptation to machine generated or human critique. Nonmonotonic reasoning, crucial to human cognition for navigating the real world, remains a challenging, yet understudied task. In this work, we study nonmonotonic reasoning capabilities of seven state-of-the-art LLMs in one abstract and one commonsense reasoning task featuring generics, such as ‘Birds fly’, and exceptions, ‘Penguins don’t fly’ (see Fig. 1). While LLMs exhibit reasoning patterns in accordance with human nonmonotonic reasoning abilities, they fail to maintain stable beliefs on truth conditions of generics at the addition of supporting examples (‘Owls fly’) or unrelated information (‘Lions have manes’).Our findings highlight pitfalls in attributing human reasoning behaviours to LLMs as long as consistent reasoning remains elusive.
Anthology ID:
2024.acl-short.51
Volume:
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)
Month:
August
Year:
2024
Address:
Bangkok, Thailand
Editors:
Lun-Wei Ku, Andre Martins, Vivek Srikumar
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
558–573
Language:
URL:
https://aclanthology.org/2024.acl-short.51
DOI:
Bibkey:
Cite (ACL):
Alina Leidinger, Robert Van Rooij, and Ekaterina Shutova. 2024. Are LLMs classical or nonmonotonic reasoners? Lessons from generics. In Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 558–573, Bangkok, Thailand. Association for Computational Linguistics.
Cite (Informal):
Are LLMs classical or nonmonotonic reasoners? Lessons from generics (Leidinger et al., ACL 2024)
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PDF:
https://aclanthology.org/2024.acl-short.51.pdf