The memory science behind Flashcardly

1. We forget fast, and on a curve

In the 1880s Hermann Ebbinghaus memorised lists of nonsense syllables and measured how much he still knew hours and days later. Forgetting was steep at first and then levelled off: the “forgetting curve”.¹ A careful replication in 2015 found the same shape.²

The useful part is what happens when you review. Each review resets the curve, and the next drop is slower. So the question isn't whether to review, but when.

2. Spaced reviews beat cramming

Spreading study sessions out works better than packing them together. A large review of verbal-learning research, covering 317 experiments, found this spacing effect again and again, and found that the best gap between reviews grows with how long you want to remember something.³ That is exactly what a Leitner schedule does: short gaps for new words, longer and longer gaps as a word proves it has stuck.

3. Recalling a word teaches you more than re-reading it

Trying to remember something, even when you get it wrong, strengthens memory more than looking at it again.⁴ In a study of foreign-language vocabulary, students who kept recalling word pairs remembered far more a week later than students who kept re-studying them.⁵ A 2013 review of ten common study techniques rated practice testing and spaced practice as the two most useful.⁶

That's why every Flashcardly card asks before it tells: you see the picture and the word, decide whether you know it, then flip.

4. The Leitner system: spacing you don't have to plan

In 1972 the German science writer Sebastian Leitner described a simple way to schedule spaced reviews with a box of cards.⁷ Cards you know move to a box you check less often. Cards you miss move back. Flashcardly runs the same idea with six boxes and schedules every review for you:

1. 0 New & missed back in 1 day
2. 1 Daily every 1 day
3. 2 Every 3 days every 3 days
4. 3 Weekly every 7 days
5. 4 About two weeks every 16 days
6. 5 About monthly every 35 days

When a word comes up for review you rate it: Don't Know drops it one box, Hard keeps it where it is and shows it again in two days, Know it moves it up one box, and Easy moves it up two. A missed word only drops one box, so one bad day never wipes out weeks of progress.

Try it with five real cards from the Spanish course:

1. 0New & missed
2. 1Daily
3. 2Every 3 days
4. 3Weekly
5. 4Every ~2 weeks
6. 5Monthly

Card 1 of 5 · in Box 0

el gato

cat

Listen

How well do you know this word?

Don't KnowHardKnow itEasy

5. Mixing it up helps too

Studying different kinds of items side by side, rather than in blocks, helps people tell them apart and remember them.⁸ Flashcardly's Mixed Practice shuffles words from different lessons across its four practice modes: Word Match, Audio Match, Sentence Builder and Type It Out. Hearing, spelling and using a word in a sentence each give your memory another way back to it.

How it fits together in the app

• Learn. Five-minute lesson parts introduce new words with a picture, native audio and an example sentence.
• Review. Each word enters the boxes and comes back on its schedule, usually 5–30 words a session.
• Practice. Games reuse the words you've learned in new ways.
• Come back. Streaks, goals and a daily reminder make the five minutes a habit.

More on each: lessons, spaced repetition, practice modes.