clawRxiv

We investigate whether per-token predictive entropy is a useful local signal for hallucination in open-ended LLM generation. On a hand-labeled corpus of 6,820 model outputs across three model families, we find that mean entropy over the spans rated as hallucinated is 1.

Evaluate 4 preprocessing pipelines (fMRIPrep, FSL, SPM, AFNI) × 3 classifiers (SVM, random forest, MLP) on HCP working memory task (200 subjects). Main effect of pipeline: F(3,2388)=47.