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Elicitation theory of post-training

As explained in Reinforcement Learning from Human Feedback

The elicitation theory of post-training is the view that post-training primarily extracts and amplifies valuable capabilities already present in a pretrained base model.

Elicitation theory views post-training as the process of extracting and cultivating capabilities already latent in a pretrained base model. Pretraining supplies broad knowledge and intelligence, but next-token prediction does not automatically produce useful question-answering behavior. section 1.4

The practical challenge is to reshape model behavior without treating post-training as the primary source of capability. Instruction fine-tuning, preference tuning, RLHF, reinforcement learning with verifiable rewards, and related methods cultivate different parts of the pretrained potential. section 1.4 section 1.7

The theory implies several implementation and evaluation considerations:

  • Measure post-training by more than response style: it can improve benchmark performance while over-optimization, such as excessive length or chattiness, harms capabilities elsewhere. section 1.7
  • Treat instruction tuning as an access mechanism rather than the complete explanation of model intelligence; narrow datasets may extract only a fraction of base-model potential. section 1.4
  • Interpret alignment partly as selecting useful interaction formats, while recognizing that post-training can cultivate substantive capabilities as well as style, tone, and format. section 1.4 section 1.7

A post-training-only improvement

OLMoE Instruct’s second version changed little of its pretraining but updated post-training; its average on popular benchmarks rose from 35 to 48. The comparison illustrates how much performance can be unlocked after pretraining. section 1.4

How Reinforcement Learning from Human Feedback covers it

How deep it goes
Explains the capability-access problem and names post-training methods, but stops short of specifying a complete optimization procedure.
Examples
Uses OLMoE Instruct benchmark gains and RLHF’s style, helpfulness, and over-optimization effects as concrete illustrations.
What it assumes
Assumes pretrained base models and next-token prediction, while distinguishing learned potential from accessible conversational behavior.
What you can do after
Evaluate post-training recipes by how effectively they unlock capability while avoiding behavioral optimization that damages other-domain performance.
How it connects
Connects pretraining with instruction fine-tuning, RLHF, preference tuning, verifiable rewards, and the Superficial Alignment Hypothesis.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Reinforcement Learning from Human Feedback. The section links point to the parts of the book it draws on.