The Science of Spaced Repetition: Why Little and Often Beats Cramming
You've probably noticed it. Your child learns their spellings on Thursday, gets them all right in the test on Friday — and has forgotten half of them by Monday.
This isn't a problem with your child. It's a well-documented feature of how human memory works. And there's a surprisingly simple technique to fix it.
The forgetting curve
In 1885, a German psychologist called Hermann Ebbinghaus discovered something important: we forget things in a predictable pattern. Without review, we lose about 50% of new information within a day, and up to 90% within a week.
He called this the "forgetting curve." And it applies to everyone — children and adults alike.
But Ebbinghaus also found the solution. If you review information at carefully timed intervals, each review strengthens the memory and slows the rate of forgetting. After enough repetitions, the information sticks permanently.
This technique is called spaced repetition.
How it works
The idea is straightforward. Instead of practising something intensively once (cramming), you practise it briefly, then come back to it after a gap. Each time, the gap gets a little longer.
For example, if your child learns a spelling word today:
- Review it tomorrow
- Then again in 3 days
- Then in a week
- Then in 2 weeks
Each review only takes seconds. But those seconds are far more effective than spending 30 minutes drilling the word once and never revisiting it.
Research published in Psychological Science confirmed that spaced practice produces "robust learning that is resistant to forgetting." It works for vocabulary, maths facts, phonics, and almost any kind of factual knowledge.
Why cramming feels effective (but isn't)
Here's the tricky part. Cramming feels like it works. If you practise something intensively right before a test, you'll probably do well. But that knowledge hasn't made it into long-term memory — it's sitting in short-term storage, and it'll fade quickly.
Psychologists call this the "illusion of competence." You feel like you know it. But you don't really know it yet.
Spaced repetition feels harder in the moment — because you're deliberately reviewing things you've half-forgotten. That effort is actually what builds the memory. The brain thinks: "I keep needing this information. I'd better store it properly."
Practical ways to use spaced repetition at home
Spelling
Instead of practising all ten spelling words the night before the test, try this:
- Monday: Introduce 5 words. Practise them.
- Tuesday: Review those 5 words. Introduce the next 5.
- Wednesday: Review all 10.
- Thursday: Review only the ones they got wrong.
- Friday: Quick run-through of all 10.
That's 5–10 minutes a day. Much less painful than a 30-minute Thursday evening session.
Maths facts
Number bonds and times tables benefit enormously from spaced repetition. A few questions each day — mixing old and new facts — is far more effective than intensive practice on one set.
Phonics
This is where spaced repetition really shines. Learning letter sounds and blending takes dozens of exposures. Brief daily practice (a few minutes of flashcards, for instance) is the fastest path to fluency.
The Leitner system — where cards move between boxes based on whether the child gets them right — is a practical implementation of spaced repetition. Cards you know well come up less often. Cards you struggle with come up more.
Spark Learn uses this approach for its phonics flashcards, automatically spacing sounds based on how well your child knows each one. It takes the guesswork out of deciding what to practise.
The "little and often" principle
You don't need to understand the neuroscience to benefit from this. The practical takeaway is simple:
A little bit every day beats a big session once a week.
- 10 minutes of reading daily > 70 minutes on Sunday
- 5 spellings reviewed daily > 20 spellings crammed on Thursday
- 3 maths questions at breakfast > a worksheet at the weekend
This is easier on your child, easier on you, and far more effective.
Making it work with a busy life
The beauty of short daily practice is that it fits into the gaps. While waiting for dinner. In the car (verbal practice). Before bedtime. Over breakfast.
It doesn't require a desk, a quiet room, or a dedicated "learning time." It just requires a few minutes and a bit of consistency.
And if you miss a day? It doesn't matter. The research shows that imperfect spacing still beats cramming. Don't aim for perfect — aim for regular.
The bottom line
Your child's brain is built to learn. It just needs information delivered in the right pattern — little and often, with gaps for the memory to consolidate.
Spaced repetition isn't a hack or a shortcut. It's how memory actually works. And once you start using it, you'll see the difference.