@inproceedings{waal-cassani-2025-cute,
    title = "Is a cute puyfred cute? Context-dependent form-meaning systematicity in {LLM}s",
    author = {Waal, Ja{\"i}r A.  and
      Cassani, Giovanni},
    editor = "Che, Wanxiang  and
      Nabende, Joyce  and
      Shutova, Ekaterina  and
      Pilehvar, Mohammad Taher",
    booktitle = "Findings of the Association for Computational Linguistics: ACL 2025",
    month = jul,
    year = "2025",
    address = "Vienna, Austria",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/landing_page/2025.findings-acl.961/",
    pages = "18747--18769",
    ISBN = "979-8-89176-256-5",
    abstract = "We investigate static and contextualized embeddings for English pseudowords across a variety of Large Language Models (LLMs), to study (i) how these models represent semantic attributes of strings they encounter for the very first time and how (ii) these representations interact with sentence context. We zoom in on a key semantic attribute, valence, which plays an important role in theories of language processing, acquisition, and evolution. Across three experiments, we show that pseudoword valence is encoded in meaningful ways both in isolation and in context, and that, in some LLMs, pseudowords affect the representation of whole sentences similarly to words. This highlights how, at least for most LLMs we surveyed, pseudowords and words are not qualitatively different constructs. Our study confirms that LLMs capture systematic mappings between form and valence, and shows how different LLMs handle the contextualisation of pseudowords differently. Our findings provide a first computational exploration of how sub-lexical distributional patterns influence the valence of novel strings in context, offering useful insights for theories on the form-meaning interface and how it affects language learning and processing."
}