The Forgetting Curve Is Real: How to Design Training That Sticks
Hermann Ebbinghaus discovered the forgetting curve in 1885. More than a century later, most training programmes still ignore it.
The science is unambiguous. Within 24 hours, we forget roughly 70% of what we learn. Within a week, retention drops to around 20%. Within a month, without reinforcement, most new learning simply disappears.
This isn't a character flaw. It's how human memory works. And until training design accounts for it, we'll keep producing programmes that feel effective in the moment but don't create lasting change.
Why the forgetting curve matters for L&D
Every training programme is an investment. Time away from work. Development costs. Opportunity costs. The question isn't just whether learners enjoyed the experience. It's whether they can still apply what they learned weeks and months later.
If 70% of training content fades within a day, the effective value of that investment shrinks dramatically. You're not building capability; you're creating temporary awareness that dissipates before it can be applied.
This explains a persistent frustration in L&D: training that evaluates well but doesn't seem to change behaviour. The feedback forms say it was excellent. The knowledge checks say learners understand. But six weeks later, nothing has changed in how people work.
The forgetting curve is usually the culprit. Not bad content. Not disengaged learners. Just the relentless decay of unrecalled memory.
What fights the forgetting curve
The antidote to forgetting is retrieval practice: actively recalling information at spaced intervals. Each time we successfully retrieve something from memory, the memory becomes stronger and more durable.
This is why cramming fails and spaced learning succeeds. The person who studies a little every day over a month will retain far more than the person who studies intensively for a weekend. The repetition at intervals is what fights decay.
For training design, this has clear implications.
Spacing matters more than duration. A programme spread over six weeks will produce better retention than the same content delivered in a two-day intensive. The calendar is a design element.
Retrieval beats review. Reading notes or watching a recording doesn't fight the forgetting curve. Being asked questions and having to produce answers does. Active recall strengthens memory in ways passive review doesn't.
Practice is a form of retrieval. When someone practises a skill, they're retrieving and applying knowledge. Each practice session reinforces the learning. This is why practice-heavy programmes produce better retention than content-heavy ones.
The timing of retrieval matters. The optimal moment to recall something is just before you would have forgotten it. This is the principle behind spaced repetition algorithms: schedule the retrieval to maximise the reinforcement effect.
Designing training for retention
Applying these principles requires rethinking how programmes are structured.
Break content into smaller units. Instead of one long learning experience, create multiple shorter ones. This naturally creates spacing and provides more opportunities for retrieval between sessions.
Build in deliberate retrieval. Don't just deliver content. Ask learners to recall and apply it. Quizzes, practice scenarios, application exercises: these aren't just assessments, they're learning activities that fight the forgetting curve.
Plan the reinforcement. Decide in advance when retrieval will happen. A touchpoint at one week, another at three weeks, another at six weeks. Each touchpoint should require active recall, not just passive review.
Use practice for reinforcement. AI roleplay tools are particularly effective for spaced retrieval. Learners practise a scenario, then practise it again a week later, then again a month later. Each practice session retrieves and reinforces the underlying skills.
Connect to real application. The ultimate retrieval is using the skill in actual work. Design programmes so that learners have opportunities to apply what they've learned soon after learning it. The application reinforces retention.
The challenge of implementation
Designing for the forgetting curve is harder than designing for engagement. It requires planning beyond the initial programme. It requires infrastructure for reinforcement. It requires accountability for ongoing practice.
Most L&D teams are measured on programme delivery, not programme retention. The incentives point toward launching new content, not reinforcing old content. Changing this requires changing how success is defined.
It also requires learner buy-in. Spaced retrieval only works if learners engage with the reinforcement activities. If the follow-up quizzes get ignored and the practice sessions get skipped, the forgetting curve wins.
Making reinforcement easy and valuable matters. If retrieval activities feel like homework, participation drops. If they feel like useful preparation for real situations, engagement stays high.
The opportunity
The forgetting curve isn't going away. It's a feature of human cognition, not a bug. But it can be worked with rather than against.
Training programmes that account for how memory actually works produce dramatically better results. The same content, designed differently, creates lasting capability instead of temporary awareness.
This is one of the highest-leverage changes an L&D team can make. Not more content. Not better production values. Just smarter sequencing and deliberate reinforcement.
The forgetting curve is real. But so are the techniques to beat it.
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