| # | Type | Target | Human Time | AI Prediction | AI Result |
|---|
Why LLMs Fail Text CAPTCHAs
Multimodal vision encoders break images into discrete patch tokens (e.g. 14×14 or 16×16 px). High-frequency salt-and-pepper noise and non-linear spline warps disrupt edge-continuity across adjacent patches, triggering hallucinations where '9' turns into 'O' or '8'.
Biological Gestalt Advantage
The primate visual cortex leverages horizontal recurrent connections in V1/V2 for contour completion and figure-ground segregation. Even when 45% of pixels are occluded by speckles or cross-lines, human perception filters noise instantly under 1500 ms.
Adversarial Vulnerability
Our benchmark tests the exact sensitivity boundary. Above 0.40 noise density and 25° rotation, simulated model accuracy falls precipitously, demonstrating why frontier models capable of passing coding exams still fail reverse-Turing tests.