Why do I forget new words a day later?
New memories fade fast unless you recall them; review each word at growing intervals, pulling it from memory before checking.
You learned a new word yesterday. Today, it's gone. That's frustrating, but your memory isn't broken. The problem is your timing. Review at the right moments, and words start to stay. This lesson shows you exactly when those moments are.
This has a name, and a shape: the Ebbinghaus forgetting curve. It drops hard at the start, because new memories fade fast. In Ebbinghaus's own tests, about half was gone within an hour, and most of it within a day. The fall is predictable, it happens to everyone, and it isn't a flaw in your brain. The answer isn't to study harder. It's to interrupt the fall at the right moment.
Cramming feels productive. You do fifty reps in one sitting, the material is right there, and it all feels easy. But that ease is a fluency illusion. Crammed memories fade fastest; they slide down the forgetting curve. You think you learned it, but it doesn't last. Research by Cepeda and colleagues shows it clearly: the same fifty reps, spread out, last far longer.
To beat the curve, you don't review more. You review on a schedule that expands. Catch a word just before it slips, then wait longer before the next look. A day. Then three days. Then a week. Then a month. Each review catches the memory lower on the curve and lifts it back to the top, and each time, the next drop is slower. The stronger the memory, the longer you can safely wait. That's why the gaps keep growing.
Re-reading a word feels efficient, but it does far less for memory than recall does. Cover the answer. Pull the word from memory. That small struggle is what makes it stick. Psychologists call it desirable difficulty. Roediger and Karpicke measured its payoff, known as the testing effect. A review you breeze through teaches you little.
Tracking the right day for hundreds of words by hand would be impossible, so you don't. A spaced-repetition system does the timing math. You recall the card, rate how hard it was, and it schedules the next review for around the time you'd start to forget. You rate it; it schedules it.
Every card you make in Synapse gets its own schedule. You recall the answer, then tap how well you remembered it, and your next review date is set for you. You just show up. No calendar, no guesswork: the timing takes care of itself.
You don't need a better memory. You need better timing for your reviews. The forgetting curve is real, but you can beat it. Space your reviews out. Make each one a recall, not a re-read. Let Synapse keep the schedule for you. And pair it with the other principles: get the pronunciation right first, and skip the translation.
