Spaced Practice
Why Cramming Fails and Spreading Out Works
The Problem: The Illusion of Learning
Your child studies intensely the night before a test. Gets a B+. Two weeks later, can't remember any of it.
Sound familiar?
Cramming works for short-term performance. It fails completely for long-term learning.
The research is clear: spacing out learning over time beats massed practice by 2-3x for retention.
The Science: Ebbinghaus and the Forgetting Curve
In 1885, Hermann Ebbinghaus conducted the first scientific study of memory. His discovery was both simple and profound:
We forget exponentially.
| Time After Learning | Memory Remaining |
|---|---|
| 20 minutes | 58% |
| 1 hour | 44% |
| 1 day | 33% |
| 1 week | 25% |
| 1 month | 21% |
This is the "forgetting curve." Without intervention, most of what we learn disappears.
But Ebbinghaus also discovered the solution: Each time you review material, the forgetting curve flattens. Information lasts longer.
Why Spacing Works
1. Retrieval Strengthens Memory
When you space practice, each session requires you to retrieve what you learned before. That retrieval (see Retrieval Practice) is what strengthens the memory.
2. Desirable Difficulty
Spaced practice is harder than massed practice. When you wait to review, you have to work harder to recall. That effort is exactly what produces durable learning.
3. Multiple Contexts
When you study the same material on different days, in different mental states, you encode it in richer ways. This makes it easier to retrieve in varied future situations.
The Research: How Much Spacing?
A massive meta-analysis by Cepeda et al. (2006) synthesized 317 experiments on spacing. Key finding:
The optimal spacing interval depends on how long you need to remember it.
| Retention Goal | Optimal Study Gap |
|---|---|
| 1 week | 1-2 days |
| 1 month | 1 week |
| 1 year | 3-4 weeks |
Rule of thumb: The longer you need to remember, the longer you should wait between study sessions.
The Bahrick Study: A 9-Year Experiment
Researchers from the Bahrick family conducted a remarkable 9-year study on learning foreign language vocabulary:
| Study Schedule | Sessions | Final Retention (5 years later) |
|---|---|---|
| 14-day intervals | 26 | Moderate |
| 56-day intervals | 13 | Higher |
The stunning result: 13 sessions with 56-day spacing produced BETTER retention than 26 sessions with 14-day spacing.
Half the work. Better results. That's the power of spacing.
Why Cramming "Works" (Sort Of)
Cramming does work — for tomorrow's test. Here's why:
| What Cramming Does | What It Doesn't Do |
|---|---|
| Gets info into short-term memory | Transfer to long-term memory |
| Feels productive | Creates durable learning |
| Produces immediate confidence | Build actual understanding |
| Works for surface-level tests | Work for application and transfer |
The problem: School rewards short-term performance. So students optimize for cramming. Then they graduate having "learned" thousands of things they no longer remember.
How ISP Applies This
Built-In Spaced Review
ISP's TimeBack platform automatically spaces review of previously mastered material:
| Feature | How It Works |
|---|---|
| Automatic review scheduling | System brings back old material at optimal intervals |
| Interleaved practice | New content mixed with spaced review |
| Retention tracking | Monitors what's fading and resurfaces it |
Your child doesn't have to manage a review schedule. The system does it.
Year-Round Learning
ISP operates year-round, not on the traditional agrarian calendar.
Why this matters for spacing:
- No 3-month "summer slide" where skills decay
- Continuous learning with built-in spacing
- Rest when needed (post-season, burnout periods) — not arbitrary 3-month breaks
Mastery + Spacing
Even after achieving mastery, concepts return for spaced review. Mastery isn't "done" — it's maintained.
What This Looks Like in Practice
Week 1: Your son masters quadratic equations. Scores 92% on the mastery check.
Week 3: During a regular session, the system surfaces a quadratic problem. He has to recall the method. (Some forgetting has occurred — that's the point.)
Week 8: Another quadratic problem appears. By now, retrieval is easier. The memory is more durable.
Month 6: When algebra builds into more complex topics, the foundation is solid because it's been spaced-reviewed repeatedly.
No cramming needed. Learning is distributed. Retention is built in.
The Spacing Effect in Sports
Athletes already know this intuitively:
| Massed Practice | Spaced Practice |
|---|---|
| 10 hours of shooting in one day | 1 hour for 10 days |
| Exhausting, diminishing returns | Fresh each session, cumulative gains |
| Skills fade quickly | Skills become automatic |
No coach would have an athlete practice a skill for 10 hours straight. Why do we do that with academic content?
How to Help at Home
Even outside ISP, you can apply spacing:
| Instead of... | Try... |
|---|---|
| Studying everything the night before | Studying a little each day for a week |
| "I already studied that" | Reviewing it again after a delay |
| Finishing a chapter and never returning | Cycling back to old chapters periodically |
| Marathon study sessions | Shorter sessions spread over time |
The challenge: Spacing feels less productive. You forget more between sessions. But that forgetting is the feature, not the bug — it's what makes the next retrieval strengthen memory.
The Research Behind This
| Researcher | Finding | Year |
|---|---|---|
| Ebbinghaus | Forgetting curve + spacing effect discovery | 1885 |
| Cepeda et al. | Meta-analysis: optimal spacing depends on retention interval | 2006 |
| Bahrick et al. | 9-year study: longer spacing = better retention | 1993 |
| Kang | Spaced repetition policy implications for education | 2016 |
| Dunlosky et al. | Distributed practice rated "high utility" | 2013 |
FAQs
Q: Won't my kid forget too much between sessions?
A: Some forgetting is necessary for the spacing effect to work. The effort of re-retrieving is what strengthens long-term memory. Trust the research.
Q: How does ISP know when to review what?
A: The TimeBack system tracks mastery and uses algorithms based on spacing research to resurface material at optimal intervals. Think of it like a smart flashcard system, but integrated into the curriculum.
Q: Is this why ISP is year-round?
A: Partly, yes. The traditional summer break causes massive forgetting (the "summer slide"). Year-round learning with built-in breaks maintains the spacing benefits without the 3-month gap.
Related Pages
- Retrieval Practice → — What to do during spaced sessions
- Interleaving → — Mixing topics for even better learning
- Desirable Difficulties → — Why "hard" is good
- Learning Science Overview → — All principles
"The secret to long-term memory isn't studying more. It's studying smarter — spread out over time."