Unnatural language processing: How do language models handle machine-generated prompts?

Corentin Kervadec, Francesca Franzon, Marco Baroni


Abstract
Language model prompt optimization research has shown that semantically and grammatically well-formed manually crafted prompts are routinely outperformed by automatically generated token sequences with no apparent meaning or syntactic structure, including sequences of vectors from a model’s embedding space. We use machine-generated prompts to probe how models respond to input that is not composed of natural language expressions. We study the behavior of models of different sizes in multiple semantic tasks in response to both continuous and discrete machine-generated prompts, and compare it to the behavior in response to human-generated natural-language prompts. Even when producing a similar output, machine-generated and human prompts trigger different response patterns through the network processing pathways, including different perplexities, different attention and output entropy distributions, and different unit activation profiles. We provide preliminary insight into the nature of the units activated by different prompt types, suggesting that only natural language prompts recruit a genuinely linguistic circuit.
Anthology ID:
2023.findings-emnlp.959
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2023
Month:
December
Year:
2023
Address:
Singapore
Editors:
Houda Bouamor, Juan Pino, Kalika Bali
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
14377–14392
Language:
URL:
https://aclanthology.org/2023.findings-emnlp.959
DOI:
10.18653/v1/2023.findings-emnlp.959
Bibkey:
Cite (ACL):
Corentin Kervadec, Francesca Franzon, and Marco Baroni. 2023. Unnatural language processing: How do language models handle machine-generated prompts?. In Findings of the Association for Computational Linguistics: EMNLP 2023, pages 14377–14392, Singapore. Association for Computational Linguistics.
Cite (Informal):
Unnatural language processing: How do language models handle machine-generated prompts? (Kervadec et al., Findings 2023)
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PDF:
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