Can LLMs Model Incorrect Student Reasoning? A Case Study on Distractor Generation for Multiple-Choice Questions

Yanick Zengaffinen, Andreas Opedal, Donya Rooein, Kv Aditya Srivatsa, Shashank Sonkar, Mrinmaya Sachan


Abstract
Modeling student misconceptions in a realistic manner is critical for AI in education. In this work, we examine how large language models (LLMs) reason about misconceptions when generating distractor answers for multiple-choice questions (MCQs), a task that requires producing answers that are incorrect, yet plausible. We introduce a taxonomy over reasoning strategies for distractor generation that is grounded in learning-science literature and empirical observation, which we apply to LLM-generated reasoning traces across math and science MCQs. On the math dataset, we find that models follow a misconception-based process with potentially high diagnostic value: they recover the correct solution, articulate student errors, simulate them, and select plausible candidates. On the science dataset, on the other hand, they tend to follow a less robust approach based on semantic similarity to the correct answer. We find the most frequent failure modes to be that the model is unable to generate a correct solution or that it discards plausible distractor candidates when performing selection. Providing the correct solution in the prompt yields a relative improvement of 6.4% in alignment with human-authored distractors, highlighting the critical role of anchoring distractor generation to the correct solution. Together, our findings offer an interpretable view of how LLMs model incorrect student reasoning.
Anthology ID:
2026.findings-emnlp.2382
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
51171–51206
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2382/
DOI:
Bibkey:
Cite (ACL):
Yanick Zengaffinen, Andreas Opedal, Donya Rooein, Kv Aditya Srivatsa, Shashank Sonkar, and Mrinmaya Sachan. 2026. Can LLMs Model Incorrect Student Reasoning? A Case Study on Distractor Generation for Multiple-Choice Questions. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 51171–51206, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Can LLMs Model Incorrect Student Reasoning? A Case Study on Distractor Generation for Multiple-Choice Questions (Zengaffinen et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.2382.pdf