Behavioural vs. Representational Systematicity in End-to-End Models: An Opinionated Survey

Ivan Vegner, Sydelle De Souza, Valentin Forch, Martha Lewis, Leonidas A. A. Doumas


Abstract
A core aspect of compositionality, systematicity is a desirable property in ML models as it enables strong generalization to novel contexts. This has led to numerous studies proposing benchmarks to assess systematic generalization, as well as models and training regimes designed to enhance it. Many of these efforts are framed as addressing the challenge posed by Fodor and Pylyshyn. However, while they argue for systematicity of representations, existing benchmarks and models primarily focus on the systematicity of behaviour. We emphasize the crucial nature of this distinction. Furthermore, building on Hadley’s (1994) taxonomy of systematic generalization, we analyze the extent to which behavioural systematicity is tested by key benchmarks in the literature across language and vision. Finally, we highlight ways of assessing systematicity of representations in ML models as practiced in the field of mechanistic interpretability.
Anthology ID:
2025.acl-long.1537
Volume:
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
31842–31856
Language:
URL:
https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.1537/
DOI:
Bibkey:
Cite (ACL):
Ivan Vegner, Sydelle De Souza, Valentin Forch, Martha Lewis, and Leonidas A. A. Doumas. 2025. Behavioural vs. Representational Systematicity in End-to-End Models: An Opinionated Survey. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 31842–31856, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Behavioural vs. Representational Systematicity in End-to-End Models: An Opinionated Survey (Vegner et al., ACL 2025)
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PDF:
https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.1537.pdf