Zero-Shot Detection of LLM-Generated Text using Token Cohesiveness

Shixuan Ma, Quan Wang


Abstract
The increasing capability and widespread usage of large language models (LLMs) highlight the desirability of automatic detection of LLM-generated text. Zero-shot detectors, due to their training-free nature, have received considerable attention and notable success. In this paper, we identify a new feature, token cohesiveness, that is useful for zero-shot detection, and we demonstrate that LLM-generated text tends to exhibit higher token cohesiveness than human-written text. Based on this observation, we devise TOCSIN, a generic dual-channel detection paradigm that uses token cohesiveness as a plug-and-play module to improve existing zero-shot detectors. To calculate token cohesiveness, TOCSIN only requires a few rounds of random token deletion and semantic difference measurement, making it particularly suitable for a practical black-box setting where the source model used for generation is not accessible. Extensive experiments with four state-of-the-art base detectors on various datasets, source models, and evaluation settings demonstrate the effectiveness and generality of the proposed approach. Code available at: https://github.com/Shixuan-Ma/TOCSIN.
Anthology ID:
2024.emnlp-main.971
Volume:
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2024
Address:
Miami, Florida, USA
Editors:
Yaser Al-Onaizan, Mohit Bansal, Yun-Nung Chen
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
17538–17553
Language:
URL:
https://aclanthology.org/2024.emnlp-main.971/
DOI:
10.18653/v1/2024.emnlp-main.971
Bibkey:
Cite (ACL):
Shixuan Ma and Quan Wang. 2024. Zero-Shot Detection of LLM-Generated Text using Token Cohesiveness. In Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing, pages 17538–17553, Miami, Florida, USA. Association for Computational Linguistics.
Cite (Informal):
Zero-Shot Detection of LLM-Generated Text using Token Cohesiveness (Ma & Wang, EMNLP 2024)
Copy Citation:
PDF:
https://aclanthology.org/2024.emnlp-main.971.pdf
Software:
 2024.emnlp-main.971.software.zip