What Changes When You Learn in Order to Teach?
The Surprising Way Teaching Others Helps You Learn.
Have you ever noticed that explaining something to someone else makes you understand it better yourself? Maybe you’ve helped a friend with a tricky subject and suddenly realised you grasp it more clearly than before. This isn’t just a coincidence—it’s backed by science.
Have you ever begun explaining something you thought you understood, only to find yourself unexpectedly stuck?
Perhaps the idea felt clear while you were reading about it. You recognised the terms. You could follow the examples. You may even have known what the next line would say.
Then someone asked:
“But why does that happen?”
And suddenly, what had felt complete became much harder to hold together.
Teaching is often recommended as a way to learn. But its value does not come simply from telling someone else what we know. Something more interesting happens when knowledge has to leave the form in which we first encountered it and become usable by another person.
Teaching changes what the knowledge is being asked to do.
The change can begin before anyone is taught
When we expect to use information only for ourselves, fragments may be enough.
We can underline a sentence, recognise a diagram or follow someone else’s explanation without having to build the whole idea for ourselves. Connections that remain implicit may not cause any trouble because the source material is still there to carry us across them.
Expecting to teach changes the destination.
In one study, people who believed they would later teach material recalled more of it and organised their recall more effectively than people who believed they would be tested. The researchers suggested that expecting to teach may have changed how learners approached the material while they were studying—not merely what they did with it afterward.
The anticipated audience appeared to matter before the audience was even present.
This does not mean that expecting to teach will always produce better learning. But it suggests that our understanding can begin changing as soon as we know it will need to become understandable to somebody else.
Private understanding can hide its own gaps
An idea can feel coherent while it remains inside the path through which we learned it.
The textbook introduces each point in order. The video supplies the transitions. The worked example shows which rule comes next. The familiar wording gives us cues that help the knowledge feel available.
Remove that path, and we may discover that some of the coherence belonged to the explanation we were following—not yet to our own understanding.
Trying to teach interrupts that borrowed fluency.
We have to decide:
- What is the central idea?
- Which details matter?
- How do the parts connect?
- What needs to come first?
- What can be left out without changing the meaning?
- What might the other person need explained?
These are not simply communication decisions. They ask us to examine the structure of what we know.
A missing connection may become visible when we cannot explain why one step follows another. A term we thought we understood may become less secure when we try to define it without repeating the original wording. Two ideas that seemed related may prove difficult to connect once we have to make the relationship explicit.
Teaching can expose gaps because it removes some of the supports that previously allowed us to move past them.
An explanation asks knowledge to do more
Explaining something draws on several kinds of activity at once.
We may need to retrieve information without looking at the source, organise it into a sequence, connect it with what the listener already knows and create examples that preserve the important features of the idea.
These demands can contribute to learning.
Research comparing different learning conditions has found benefits from preparing to teach and from producing an explanation. In some studies, learners who actually taught material performed better on later tests of understanding than learners who only restudied it or prepared to teach it.
One possible reason is retrieval. When we teach without reading directly from our notes, we have to bring the knowledge back to mind. Retrieval is not merely a way of checking whether something has been learned; the act of retrieving can strengthen later access to it.
But teaching may ask for more than retrieval alone.
A useful explanation cannot simply release everything we remember in the order it returns. It has to give the information shape. We need to select, organise and connect. We may need to move between a principle and an example, or approach the same idea from several directions.
The knowledge is no longer being asked only to reappear.
It is being asked to hold together.
The listener changes the task
It is possible to prepare a polished explanation that follows exactly the route we expected.
Then the listener asks a question.
Perhaps they misunderstand something we assumed was obvious. Perhaps they offer an example that does not quite fit. Perhaps they ask what would happen if one of the conditions changed.
The prepared route is no longer enough.
Questions can require us to inspect the knowledge from another position. We may have to rearrange it, distinguish between ideas that looked similar or apply a principle in circumstances we did not rehearse.
This interaction can be valuable because the listener does not necessarily share our assumptions. They can reveal what our explanation depended on without our noticing.
Research into learning by teaching suggests that interaction may sometimes create additional opportunities for learning—but the effect depends on what the interaction asks the person teaching to do. A listener who simply receives an explanation creates a different task from one who asks questions, identifies contradictions or needs the idea represented another way.
It is not the presence of another person alone that creates the learning.
It is what becomes necessary because they are there.
A clear explanation is evidence—but not proof
Teaching can reveal something about our capability. It does not reveal everything.
Someone may be able to give a fluent explanation but struggle to apply the knowledge in a new situation. They may reproduce an account accurately without understanding why it works. They may simplify a difficult idea until an important distinction disappears.
An explanation can also contain an error that neither the speaker nor the listener recognises. Without reliable information or feedback, teaching may strengthen the organisation and retrieval of a misconception rather than correct it.
This is why the familiar claim—
“If you can explain it simply, you truly understand it”
—goes too far.
Explaining something clearly is meaningful evidence. It may show that we can retrieve, organise and communicate particular parts of our knowledge. But capability depends on what we are trying to do.
Can we recognise the idea?
Recall it?
Explain it?
Use it?
Adapt it when the conditions change?
Respond to a question we did not anticipate?
Each task may reveal something different. Being able to teach an idea does not automatically mean we can perform every task associated with it. Equally, struggling to explain it does not erase the parts that are already working.
The explanation gives us a view—not a final verdict.
Teaching does not always help in the same way
The phrase learning by teaching can make teaching sound like a single, reliably effective technique.
In practice, it can describe very different activities:
- expecting to teach while studying
- preparing an explanation
- explaining aloud from memory
- writing for an imagined audience
- teaching someone who asks questions
- teaching with access to feedback
- repeating a prepared account with notes in front of us
These tasks do not place the same demands on the learner, so we should not expect them to produce identical results.
Prior knowledge matters too.
When the foundations are still forming, constructing an explanation may demand so much attention that there is little capacity left for examining the idea itself. A learner may need examples, prompts or feedback before teaching becomes useful. Someone with more developed knowledge may be better able to notice relationships, select examples and respond when the explanation moves beyond the planned path.
The benefit is not produced by occupying the role of “teacher.”
It comes from the thinking the teaching task makes possible—and whether the learner has enough support to engage in that thinking.
What teaching can let us see
Teaching can be valuable because it changes the conditions under which we encounter our own knowledge.
What felt clear with the source in front of us has to be retrieved.
What felt connected has to be organised.
What remained implied has to be made visible.
What worked along one familiar path may have to move in a new direction.
Sometimes the explanation holds together. Sometimes a question reveals a gap. Sometimes we discover that we understand one part well and another only when the original supports remain in place.
None of those outcomes needs to become a verdict on whether we are “good at” the subject.
They are information about what the knowledge can do at this point—and what it may need next.
Teaching does not simply give us another opportunity to repeat what we know.
It gives our knowledge a different job—and, in doing so, may allow us to see more clearly what is taking shape.
How to Use Teaching as a Study Strategy
You don’t have to be a teacher to benefit from this approach. Here are ways to integrate teaching into your learning routine:
✅ Teach a friend or study group – Even if they’re not in your subject, explaining aloud helps you structure your thoughts.
✅ Teach an imaginary student – Talk out loud as if you’re teaching someone who knows nothing about the topic.
✅ Write out your explanation – Create a guide, a blog post, or even micro-content cards that explain concepts in simple terms.
✅ Use micro-content cards – Instead of just reading facts, turn them into “teach-back” prompts where you explain the idea from memory.
Research behind this article
Nestojko, J. F., Bui, D. C., Kornell, N., & Bjork, E. L. (2014). Expecting to teach enhances learning and organization of knowledge in free recall of text passages. Memory & Cognition, 42, 1038–1048. View study
Fiorella, L., & Mayer, R. E. (2013). The relative benefits of learning by teaching and teaching expectancy. Contemporary Educational Psychology, 38(4), 281–288. View study
Kobayashi, K. (2019). Interactivity: A potential determinant of learning by preparing to teach and teaching. Frontiers in Psychology, 9, 2755. View review
Lachner, A., Hoogerheide, V., van Gog, T., & Renkl, A. (2022). Learning-by-teaching without audience presence or interaction: When and why does it work? Educational Psychology Review, 34, 575–607. View review