Meta-Learning: Why It’s Hard and What We Can Do

Meta-learning (or learning to learn) studies how to use machine learning to design machine learning methods themselves. We consider an optimization-based formulation of meta-learning that learns to design an optimization algorithm automatically, which we call Learning to Optimize. Surprisingly, it turns out that the most straightforward approach of learning such an algorithm, namely backpropagation, does not work. We explore the underlying reason for this failure, devise a solution based on reinforcement learning and discuss the open challenges in meta-learning.