How to remember what you learn in online courses: 5 research-backed methods

Rootlet

Wed, 14 Oct 2026

Finishing an online course feels great. Remembering it a month later is harder. The good news is that learning researchers have tested which study habits actually make knowledge stick, and the ones that work best are simple, free and easy to fit around a video course. This guide covers five of them, what the evidence says about each, and exactly how to use them on Rootlet.

Why rewatching feels like learning (but often isn't)

Most people revise by going over the material again. In a survey of 177 university students, 83.6% said they reread their notes or textbooks, while only about 1 in 10 said they tested themselves.

The problem is that going over familiar material makes it feel easy, and "easy" feels like "learned". In a well-known experiment, students who restudied a passage did better on a test five minutes later, but students who practised recalling it remembered substantially more two days and one week later, even though the restudying group felt more confident. A major review of ten popular study techniques rated rereading and highlighting as low utility, and rated two techniques as high utility: practice testing and spreading study out over time. Those two come first below.

1. Test yourself instead of rewatching

Pulling information out of your memory strengthens it more than putting it in again. Researchers call this retrieval practice. In one study, students who read a science text and then recalled it from memory scored about 50% higher on a test a week later than students who studied the same text by drawing concept maps. Most students had predicted the opposite.

It also helps while you watch. In a study of an online video lecture, students who were given short tests between segments mind-wandered about half as often, took more notes and remembered more than students who weren't tested.

How to do it on Rootlet

• At the end of each lesson, pause and write down (or say out loud) the three main points without looking. Then check what you missed.
• Before you start the next lesson, spend a minute recalling what the last one covered.
• Use any quizzes in your course, and take them before you feel "ready". Getting things wrong and then checking the answer is part of how it works.
• Turn headings from your notes into questions ("What are the three types of...?") and answer them from memory a few days later.

2. Space your learning out

Studying in several shorter sessions spread over days beats one long session, even when the total time is the same. This is one of the most consistently replicated findings in memory research. A study of over 1,300 people found the best gap between reviews depends on how long you want to remember something: to remember for a week, review after a day or two; to remember for a year, the gap can stretch to weeks.

How to do it on Rootlet

• Aim for a few sessions a week rather than one marathon. Because courses are self-paced, you can choose a rhythm that fits around work and family.
• Come back to earlier lessons after a few days and a few weeks, and quiz yourself on them before you rewatch anything. Once you've bought a course, you keep access, so you can return to it whenever you need a refresher.
• Put short review sessions in your calendar so they actually happen.

3. Mix things up

When a course teaches several related techniques, it's tempting to practise one until it feels solid, then move on to the next. Mixing them together, called interleaving, is harder but tends to stick better, because you have to work out which approach each problem needs. In one experiment, students who practised maths problems in a shuffled order performed far better on a test a week later than students who practised one problem type at a time. The review mentioned above rates interleaving as moderately useful, with most of the evidence coming from maths and visual skills.

How to do it on Rootlet

Once you've covered a few sections, set yourself practice that mixes them. For example, if you're learning spreadsheets, write a list of small tasks that need different formulas and do them in a random order rather than section by section.

4. Take notes in your own words

Copying down what an instructor says word for word is a bit like rewatching: it feels productive but asks little of your memory. Notes work harder for you when you have to think. The same review of study techniques rates self-explanation (explaining to yourself how a new idea works or how it connects to what you know) as moderately useful.

How to do it on Rootlet

• Watch a short chunk, pause, and then write what you understood in your own words without rewinding.
• Add a line on why it works or when you'd use it, not just what it is.
• Mark anything you couldn't explain, then rewatch just that part. Rewatching is most useful when you know exactly what you're looking for.

5. Use it on something real

The best way to make a skill yours is to use it. Across 225 studies of university science, engineering and maths classes, students in traditional lecture-only courses were about 1.5 times more likely to fail than students in courses with active learning, where they worked on problems and applied ideas. Those were classroom courses rather than online ones, but the principle carries over: doing beats watching.

How to do it on Rootlet

• Pick a small, real project before you start the course, such as a budget spreadsheet, a logo for a friend, or a short piece of code that automates a chore.
• After each section, apply what you just learned to that project, even roughly.
• When you get stuck, that's useful: it shows you exactly which lesson to go back to.

Putting it together: a simple routine for each lesson

1. Before: spend one minute recalling what the last lesson covered.
2. During: pause every few minutes and note the key idea in your own words.
3. After: close the video and write the main points from memory, then check.
4. Apply: use the lesson on your project, even for ten minutes.
5. Later: a few days on, quiz yourself on it again before moving too far ahead.

Some Rootlet courses unlock lessons one at a time as you go, so you'll need to watch most of each lesson before the next one opens. That works well with this routine: use the moment before the next lesson unlocks as your cue to recall what you've just watched.

None of these methods will feel as smooth as watching the video again, and that's the point. Learning that feels a little effortful is usually learning that lasts.

Ready to try it? Browse the courses on Rootlet and pick something you'd like to learn properly.

Sources

• Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J. and Willingham, D. T. (2013). Improving students' learning with effective learning techniques. Psychological Science in the Public Interest, 14(1).
• Roediger, H. L. and Karpicke, J. D. (2006). Test-enhanced learning: taking memory tests improves long-term retention. Psychological Science, 17(3).
• Karpicke, J. D. and Blunt, J. R. (2011). Retrieval practice produces more learning than elaborative studying with concept mapping. Science, 331. Summary: Purdue University news release.
• Szpunar, K. K., Khan, N. Y. and Schacter, D. L. (2013). Interpolated memory tests reduce mind wandering and improve learning of online lectures. PNAS, 110(16).
• Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T. and Pashler, H. (2008). Spacing effects in learning: a temporal ridgeline of optimal retention. Psychological Science, 19(11).
• Rohrer, D. and Taylor, K. (2007). The shuffling of mathematics problems improves learning. Instructional Science, 35.
• Karpicke, J. D., Butler, A. C. and Roediger, H. L. (2009). Metacognitive strategies in student learning: do students practise retrieval when they study on their own? Memory, 17(4).
• Freeman, S. et al. (2014). Active learning increases student performance in science, engineering, and mathematics. PNAS, 111(23).