When students engage in productive struggle—persevering through problems while thinking flexibly—they move from surface learning to deep learning. In the brain, this move is aided by the formation of myelin, a fatty substance that speeds up and strengthens brain signals by wrapping around the axons that connect neurons. "A well-myelinated brain signal travels over 100 times faster than an unmyelinated brain signal," writes Rishi Sriram.⁠ ⁠ Sriram suggests four strategies to enhance students’ learning through productive struggle:⁠ ⁠ 1. Retrieval: Giving frequent practice tests forces the retrieval of memories—which tells the brain “to make those signals more permanent,” writes Sriram.⁠ ⁠ 2. Interleaving: Mixing old and new material significantly improves long-term performance, so include questions from past lessons on current tests, and take a few minutes each day to review previous concepts to deepen learning.⁠ ⁠ 3. Spacing: "Students benefit more from frequent, shorter sessions than f...