Inverse Turing Bench: Evaluating Language Models as Judges of Human vs. AI Dialogue

William Hager, Ishika Rathi, Masum Hasan, Cameron Robert Jones


Abstract
As AI systems integrate into online spaces, differentiating them from humans in conversations is increasingly important. We present INVERSE TURING BENCH, a benchmark that evaluates LLMs and other models on their ability to differentiate humans and AI in multi-turn text. The benchmark provides a collection of paired dialogue transcripts, wherein one dialogue is between two humans and the other is between a human and an AI. The task is to correctly identify which dialogue is human-only vs. human-AI. We evaluated a preliminary set of models against this benchmark, and found that GPTZero, Claude Opus-4.6, and GPT-5.5 achieve the highest accuracy: 89.41%, 77.92%, and 75.94% respectively. Our results suggest that statistical approaches to detection have semantic blind spots, but semantic approaches are susceptible to persona-prompting. Our work speaks to the Inverse Turing Test and motivates human-AI differentiation as a critical capability for AI systems. Our live benchmark can be found at https://huggingface.co/spaces/roc-hci/Inverse-Turing-Bench-Leaderboard
Anthology ID:
2026.luhme-1.25
Volume:
Proceedings of the 3rd Workshop on Language Understanding in the Human-Machine Era (LUHME 2026)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Rui Sousa-Silva, Henrique Lopes Cardoso, Maarit Koponen, Antonio Pareja-Lora
Venues:
LUHME | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
378–388
Language:
URL:
https://aclanthology.org/2026.luhme-1.25/
DOI:
Bibkey:
Cite (ACL):
William Hager, Ishika Rathi, Masum Hasan, and Cameron Robert Jones. 2026. Inverse Turing Bench: Evaluating Language Models as Judges of Human vs. AI Dialogue. In Proceedings of the 3rd Workshop on Language Understanding in the Human-Machine Era (LUHME 2026), pages 378–388, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Inverse Turing Bench: Evaluating Language Models as Judges of Human vs. AI Dialogue (Hager et al., LUHME 2026)
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PDF:
https://aclanthology.org/2026.luhme-1.25.pdf