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Term

RLHF

Reinforcement Learning from Human Feedback — training procedure that aligns models with helpful and safe behavior using human preference comparisons.

RLHF — in more detail

RLHF (Reinforcement Learning from Human Feedback) is the standard recipe by which modern chat models like ChatGPT, Claude or Gemini acquire their helpful, friendly and safe response style. The pipeline typically has three stages: first, supervised fine-tuning on high-quality example answers. Second, training a reward model on pairwise human preference comparisons (“answer A is better than answer B”). Third, reinforcement-learning optimization of the language model against this reward model, often using the PPO algorithm.

Example / practical context

Without RLHF, language models behave much more like raw text completers: a question may be answered by another similar question, because training text often contains lists of similar questions. RLHF aligns the model with what humans actually consider a helpful answer. Newer methods such as DPO (Direct Preference Optimization) replace the classic RL step and skip the explicit reward model entirely while keeping the same core idea — learning from preference data.

Delineation from similar terms

RLHF aligns the model with human preferences, while fine-tuning in a narrower sense only learns from new examples. RLAIF (“from AI Feedback”) uses AI-generated comparisons instead of human ones to scale the most expensive step. Constitutional AI is Anthropic’s variant, evaluating responses against an explicit set of principles.

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