MIT 6.7960 L18: Transfer Learning — Pretraining, Feature Extraction, and Fine-Tuning Strategies
Transfer learning's core insight is 'features learned on big data are good general-purpose representations': freeze the backbone and train only a linear head when downstream data is tiny; full fine-tune when data is plentiful; reach for LoRA / adapter when compute is tight. SimCLR and MAE removed the need for upstream labels and pushed downstream quality another notch.