The forgetting curve and what it means for learning vocabulary

You learn a word on Monday and feel sure about it. On Friday you see it again and think: I knew this. If that feels familiar, you have experienced the forgetting curve.

Ebbinghaus and the curve

In the late nineteenth century, the German psychologist Hermann Ebbinghaus ran some of the first systematic memory experiments. He used himself as the subject, memorized lists of nonsense syllables and measured how much he could recall after different delays. He published the results in 1885.

The pattern that emerged is now known as the forgetting curve:

• Forgetting right after learning is fast.
• It then slows down, flattening out over time.
• Information that is reviewed fades more slowly than information that is not.

Exact percentages depend on the experiment and the person, so treat the neat charts with specific numbers that circulate online with caution. The useful takeaway is the shape.

What it means for vocabulary

1. The first days matter most. If you meet a word once and never again, it spends the steepest part of the curve unreviewed.
2. Several small reviews beat one big one. The same total time is more durable when spread out.
3. Reviewing when it is harder, but still possible, helps. Recalling a word just as it is slipping strengthens memory.

Put together, these three points give you spaced repetition, explained in what is spaced repetition.

How to flatten the curve in practice

See the word again soon

Meeting a new word a second time shortly afterwards, and trying to recall it, softens the steepest part.

Space reviews further apart as you succeed

Each time you recall a word, wait a little longer before the next review. When you fail, shorten the gap. Doing this by hand is tedious; cards or apps help.

Recall actively

Looking at a list and thinking “yes, I know that” is not a recall test. Cover the answer and test yourself.

Make it meaningful

Meaningful, contextual information fades more slowly than isolated facts. Learn words in sentences, with audio and with your own examples. More techniques in how to memorize vocabulary.

What the curve does not tell you

The curve describes how memory behaves in general. It does not:

• say exactly how many reviews a given word needs,
• replace the practice of producing the word in speech or writing, or
• guarantee that a word is permanent after a set number of days.

A small example plan

The plan below is only an illustration, not a scientific prescription.

Run by hand, this calendar gets complicated as new words pile up each day. That is where a system helps.

Frigya and the curve

In its Learn stage, Frigya asks the words you have met again using spaced repetition; its Google Play listing says the aim is to review words at the right time, following the forgetting curve. The progress screen shows how many words are due for review today, so you can see your daily load. See how many words a day for choosing a goal.

Understanding the experiment and its limits

Ebbinghaus’s work was a landmark, but it has limits worth knowing:

• He used nonsense syllables. This removed the effect of meaning. Real words carry meaning, imagery and context, so they are generally forgotten more slowly than nonsense syllables.
• He was the only subject. Later research found similar patterns in other people, but exact figures vary from person to person.
• The curve depends on learning conditions. How well you learned, your interest, sleep and the number of reviews all change its shape.

So treat the forgetting curve as a strong, general tendency and not as a law. The practical conclusion stays the same: unreviewed information fades quickly, and spaced reviews slow that down.

Noticing the curve in your own study

You can spot it in your own experience:

• On the day you learn a word you recall it easily; two days later you get the feeling “it’s there but not quite coming”. That is the steep part.
• A week on, you recognise the word when you see it but struggle to produce it. That is the gap between recognition and recall.
• After recalling it successfully at several different times, a month later you still think “yes, that one”. That is review flattening the curve.

This matters because recognising and recalling are different tasks. You may pick the right option in a multiple-choice question but fail to produce the word on a blank page.

Three small rules for managing the curve

Rule 1: Do the first review early. The first review, on the same or the next day, cuts off the steepest part of the curve.

Rule 2: Reward successful recall. If you recalled a word, push the next review a little further out. If you did not, shorten the gap.

Rule 3: Avoid overload. The enemy of managing the curve is adding too many new words in one day. More words means more curves to manage. See how many words a day.

Common misunderstandings

• “Ten repetitions and it’s mine forever.” No; the timing of the repetitions matters more than the count.
• “Forgetting is failure.” Forgetting is a normal part of learning, and recalling after forgetting strengthens memory.
• “I should only review hard words.” Easy words fade too; they simply need rarer reviews.

Summary

• The forgetting curve: fast loss after learning, then slower loss.
• Reviews make the curve shallower.
• Spread-out, recall-based reviews are the efficient route.
• Trust the shape, not exact figures.