The response length of reasoning language models (LLMs) increases for ill-posed questions with missing premises (MiP), leading to redundant and ineffective thinking.
This scenario exacerbates the overthinking issue, which is named as MiP-Overthinking.
LLMs not specifically trained for reasoning perform better on the MiP scenario, producing shorter responses and quickly identifying ill-posed queries.
The current training recipe for reasoning LLMs lacks efficient thinking and encourages overthinking, indicating a critical flaw.