Augustinian BabyLM: What Ostensive Definition Can and Cannot Teach a Small Language Model

Lisa Bylinina


Abstract
A language model normally begins training with random word embeddings: whatever ’banana’ means must be learned from training corpora. I implement St. Augustine’s picture of word learning, meaning by ostension, for a small masked language model (DeBERTa) trained on 10M words: before training, visually grounded tokens receive embeddings derived from the image regions they label; other tokens start random.

Visual initialization leaves a measurable imprint that lasts until the end of training. At the same time, the effect remains invisible under most BabyLM benchmarks, which probe abstract grammatical knowledge: visual initialization does not affect performance there. The only zero-shot exception is object-property knowledge (COMPS), where seeding helps in every configuration. To follow up on this result, I build a corpus-tailored version of the Visual-Property Swap benchmark, which tests color, material, size, and shape knowledge, with per-item training frequency and seeded status. Here, vision-seeded models have a persistent, seed-replicated advantage, confined to the seeded words. As a causal test, I show that synthetic grounding of previously unseeded words transfers the advantage to exactly those words.

Function words and abstract vocabulary also receive strong visual seeds and retain them throughout training, and the training objective draws on them: held-out mask-prediction loss falls for these words in every seed. However, no benchmark I run registers this. What evaluation would pick this up remains an open question.
Anthology ID:
2026.babylm-main.13
Volume:
Proceedings of the Second BabyLM Workshop
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Leshem Choshen, Ryan Cotterell, Mustafa Omer Gul, Jaap Jumelet, Tal Linzen, Aaron Mueller, Suchir Salhan, Raj Sanjay Shah, Alex Warstadt, Ethan Gotlieb Wilcox
Venues:
BabyLM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
165–178
Language:
URL:
https://aclanthology.org/2026.babylm-main.13/
DOI:
Bibkey:
Cite (ACL):
Lisa Bylinina. 2026. Augustinian BabyLM: What Ostensive Definition Can and Cannot Teach a Small Language Model. In Proceedings of the Second BabyLM Workshop, pages 165–178, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Augustinian BabyLM: What Ostensive Definition Can and Cannot Teach a Small Language Model (Bylinina, BabyLM 2026)
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PDF:
https://aclanthology.org/2026.babylm-main.13.pdf