I had already built the courses. Interactive, with a live code editor, quizzes, diagrams, bilingual. I was rather proud of them. Then I read an MIT EEG study on cognitive debt, and another on the widening gap between learners in the age of AI. They made me uneasy, because they described a trap my own courses might be falling into: giving the illusion of learning while anchoring nothing for the long term.
So I reworked everything. Here is what I changed, why, and how I rolled it out across 109 lessons without spending three months on it. It's a retrospective that's as pedagogical as it is technical. (For the science itself, I cover it in a dedicated article.)
The problem my courses couldn't see
My lessons were smooth. You read a clear explanation, watched a working example, ticked a multiple-choice quiz, moved on. Pleasant. And that's exactly the trap: the science of learning is clear, felt fluency is not learning. The easier it feels in the moment, the less it stays.
My quizzes came right after the theory: they tested working memory, not durable memory. My editors showed the solution before the learner had made the effort to find it. My multiple-choice was recognition (pick the right answer), not production (write it from memory). And nothing brought notions back over time. In short, I was sanding away every friction, when the good frictions are precisely what carves things in.
