Paul Christiano

American AI safety researcher — former OpenAI safety team lead — founder of the Alignment Research Center (ARC) — who invented RLHF (Reinforcement Learning from Human Feedback) in its original conceptual form — the most technically sophisticated AI safety researcher.

Creates RLHF as a proposed alignment approach — Christiano's original RLHF paper (using human comparative feedback to train AI systems rather than explicit reward specification) became the training technique behind ChatGPT; his broader research on AI interpretability and oversight represents the most rigorous technical alignment work.