Redwood Research Questions Whether GDM Intentionally Trains Gemini 4 on Chain of Thought

Redwood Research says it is unclear whether Google DeepMind intentionally trains Gemini 4 on chain of thought, after the Gemini 4 Safety report cited an auxiliary reward that observes thoughts as context. GDM staff told Redwood they were not training on CoT but could not explain the technical details, while a GDM blog post says the model is never penalized for what it writes in its chain of thought. Redwood warns that CoT rewards biased against misaligned reasoning could suppress honest verbalization and reduce CoT faithfulness.