The method, part 2
How to remember new words: spaced repetition and retrieval practice
Learning a word is easy. Keeping it is the hard part. Two of the best-documented findings in memory research tell us how: review at growing intervals, and test yourself instead of rereading.
The forgetting curve
In the 1880s Hermann Ebbinghaus memorised lists of nonsense syllables and measured how much he still remembered after hours and days. Forgetting was fastest right after learning and then slowed down1. A careful replication in 2015 produced a very similar curve2.
The same happens to a new word from a book. If you never meet it again, it fades within days. Each successful review, though, makes the memory more stable, so the next drop is slower.
Without reviewsWith reviewsdays →
Spacing beats cramming
Reviewing the same material spread over time works better than the same amount of practice in one sitting. A meta-analysis of 317 experiments confirmed this spacing effect and found that the best gap between reviews grows the longer you want to remember something3.
A 2013 review of ten popular study techniques rated only two as having high utility: distributed practice (spacing) and practice testing4. Highlighting and rereading, the most common habits, were rated low.
Test yourself instead of rereading
In a study published in Science, students learned 40 Swahili–English word pairs. Those who kept practising recall remembered about 80% of the words a week later. Those whose words were dropped from testing once they knew them remembered only 36% and 33%, even when they continued to study them5.
The effort of pulling a word out of memory is what strengthens it. Tasks that make you think harder about a word, such as choosing the right word for a gap in a sentence, also lead to better retention than simply seeing it again6.
The Booklex schedule: 1, 3, 7 and 21 days
Booklex uses a simplified version of the Leitner system, a box-based method of spaced flashcards described by Sebastian Leitner in the 1970s7. Every saved word climbs a ladder of intervals:
- Saved
- Day 1
- Day 3
- Day 7
- Day 21
- Learned
- Correct answer: the word moves to the next interval: 1, then 3, then 7, then 21 days.
- Mistake: the word goes back to today’s queue and starts again, because that is the word you need most.
- Reviewing early does not count. Practising a word before it is due will not push it up the ladder, so you cannot “finish” all intervals in one evening.
- Five correct answers in a row and the word is marked as learned, leaving room for new ones.
Five exercises, from recognising to recalling
Seeing a word, choosing it and producing it are different skills, so each word goes through five different tasks:
- 1Flash Cards
- 2Quiz Test
- 3Fill the Gap
- 4Memory Game
- 5Word Puzzle
- Flash Cards: see the word, try to recall the meaning, then check.
- Quiz Test: pick the right translation among several options.
- Fill the Gap: put the word into a real sentence, which forces you to think about its meaning and use.
- Memory Game: match words with their translations.
- Word Puzzle: build the word letter by letter, so you remember how it is spelled.
In Daily practice Booklex takes six words, starting with the ones due for review, and runs them through all five exercises in a row. It takes a few minutes. Reminders show you a word from your list without the translation, so even the notification is a small recall exercise.
How to make it a habit
- Little and often. Five minutes every day works better than an hour on Sunday.
- Do the due words first. They are the ones about to be forgotten, so reviewing them now gives the biggest return.
- Save words while you read. The best words to learn are the ones from your own book, because you have already seen them in a story you care about.
Not sure which words to learn? Start with part 1: learning vocabulary through reading.
Frequently asked questions
How often should I review new words?
Soon after learning, then at growing intervals. Booklex reviews words after 1, 3, 7 and 21 days; a mistake sends the word back to the start so it gets extra practice.
What is the Leitner system?
A spaced-repetition method from the 1970s: flashcards move to the next box when you answer correctly and back to the first box when you make a mistake, and later boxes are reviewed less often. Booklex follows the same idea with fixed intervals of 1, 3, 7 and 21 days.
How many new words should I learn a day?
It is better to learn a few words well than many words badly. Booklex’s daily practice works with six words at a time; you can do more sessions whenever you like.
Is spaced repetition better than rereading word lists?
Yes. Research consistently shows that testing yourself at spaced intervals leads to much better long-term memory than rereading the same material.
Sources
- Ebbinghaus, H. (1885). Über das Gedächtnis. Leipzig: Duncker & Humblot. (English: Memory: A Contribution to Experimental Psychology, 1913.) psychclassics.yorku.ca/Ebbinghaus/index.htm
- Murre, J. M. J., & Dros, J. (2015). Replication and analysis of Ebbinghaus’ forgetting curve. PLOS ONE, 10(7), e0120644. 10.1371/journal.pone.0120644
- Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380. 10.1037/0033-2909.132.3.354
- Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013). Improving students’ learning with effective learning techniques. Psychological Science in the Public Interest, 14(1), 4–58. 10.1177/1529100612453266
- Karpicke, J. D., & Roediger, H. L. (2008). The critical importance of retrieval for learning. Science, 319(5865), 966–968. 10.1126/science.1152408
- Laufer, B., & Hulstijn, J. (2001). Incidental vocabulary acquisition in a second language: The construct of task-induced involvement. Applied Linguistics, 22(1), 1–26. 10.1093/applin/22.1.1
- Leitner, S. (1972). So lernt man lernen. Freiburg: Herder.
