TheSequence β’ 161 implied HN points β’ 19 Feb 26
- AI development has two stages: pre-training builds a raw base model, and post-training (like SFT and RLHF) puts a behavioral "mask" on it so it acts helpful, safe, and fluent.
- Post-training interpretability is a distinct focus that studies how knowledge is modulated, suppressed, or amplified during fine-tuning, asking not just what the model knows but why it chose to say one thing instead of another.
- As models get more capable and the alignment cost falls, understanding post-training interventions becomes increasingly important and is becoming a key research frontier with new techniques emerging.