Active learning: optimise for retention

Students that take a conventional lecture, forget around 90% of the material within 6 months. In an active learning environment students can retain more than 70% of what they have learned two years later. Active learning means you participate, collaborate with others, and apply concepts to the real world. It requires hard mental effort but leads to better retention and an understanding of the material that can be transferred to other situations.

To explain this important topic and how to apply Active Learning in classrooms, we collaborated with Professor Carl Wieman, a Nobel Prize winning physicist, who researches and champions the approach. Prof. Wieman helped us proofread, fact check and write the script — he was an invaluable source of information. It was our greatest honor to be able to work with a mind as bright as his. 

The full story
Active Learning

“Active learning” means you participate, collaborate with others, and apply concepts to the real world. It requires hard mental effort but leads to better retention and an understanding of the material that can be transferred to other situations.

The two fundamental questions

To understand why active learning works so well, it helps to know that when our brain decides what to remember, it asks itself two fundamental questions: Can I understand? And do I need to know?

Can I understand?

When you ask “Can I understand?” your brain always puts the new information on the foundation of existing knowledge. If the foundation is missing the brain has no idea what to do with it and as a result, it throws it away. In other words, your brain needs to build foundational neuron connections for new information to attach to – which is both why active learning is more mental work, but also essential for learning.

Do I need to know?

When we ask ourselves: “Do I need to know?” Our brain separates between the material it finds worth remembering and what it can forget. If it’s unlikely that new information will ever be used again, the brain is smart enough to throw it away. If your brain finds that the information is needed again, say it could increase your social status, the brain will store it in long-term memory. To stay there and be easily recalled, you just have to periodically use or think of it.

Active learning in the classroom
carl wieman

To understand how active learning is applied in classrooms, let’s look at the teachings of Prof. Carl Wieman, a Nobel Prize winning physicist and a leading proponent of the method. There are four steps to it.

Step 1: Preparation
active learning first step

Prior to class, the students read up on the fundamentals of the lesson, so they get an idea of the terms and basic phenomena. In class, Professor Wieman starts with a brief introduction and then gives questions to solve. He will have students use clickers, a little device on which students can answer multiple-choice questions. Alternatively or for more complex problems, worksheets can be handed out.

Step 2: Survey with clickers (5 mins)
active learning step 2

Wieman projects a problem and asks all the students to select one of three possible answers using their clicker. This has two benefits: First, the teacher gets an idea of how many of his students already understand the topic, and second, the students are now focused on the question. They want to know if they were right! It is important though that the question is both challenging and interesting. All this takes less than 5 minutes.

Step 3: Peer discussions and 2nd survey (7 mins)
active learning step 3

Without telling the students how they voted and following Eric Mazur’s Peer Instruction Method — which involves questions, peer discussions, votes and group discussions — the students then discuss the question and their answers with one or two classmates, ideally with someone who disagrees with their own opinion.


During the discussion, the students have to come up with a reason for their answer and why the others may be wrong. Meanwhile, the instructor is circling around, listening in to gauge student thinking, and answering brief questions.


Then there will be a second clicker vote. And only now the results will be shown. Typically the second vote will be much better than the first as students learn a great deal from their discussions. An ideal question will have about ⅓ correct on the first vote and 85% correct on the second. All this takes around 7 minutes.

Step 4: Follow-up discussions and answers (10 mins)
active learning step 4

Now the professor leads a follow-up discussion with all the students to provide feedback, exploring the different reasoning, which one is correct, and importantly, which is incorrect and why?


Only at the very end, professor Wieman will explain the correct solution and answer follow-up questions. Ascertaining the students’ understanding from the questions they ask, he decides if it is time to move on. All of which takes around 10 minutes.

Three reasons active learning works

The students are actively working on interesting problems. And as they all voted for an answer right at the beginning, they have a stake in the outcome. That means their brains decide that the information covered is important to be remembered and are hence more receptive to learning.

problem solving

By solving problems alone and in groups they dive deeply into the material. Explaining to a peer engages novel mental processes. As a result they construct new synaptic pathways inside their brains.


The explanation from the teacher comes only once the students have already formed their own thoughts about the concept. At this point, the explanation makes more sense as the brain can connect the new information to all the thoughts it has just built. The correct answers have a solid foundation.

Passive vs. active learning

A large body of research has shown big differences in the outcomes between passive and active learning. In one carefully executed experiment, physics instructors taught their course in two ways: some classes were taught in a conventional style and others using active learning. Even though the teachers were the same and the students were similar, on average the active learners doubled their understanding when they were tested at the end of the course.

active vs passive

Other experiments have shown that long term retention is higher as well. Students that take a conventional lecture that is followed by a test, forget around 90% of the material within 6 months. In an active learning environment students can retain more than 70% of what they have learned two years later.

The myth of classic instructions
conventional teaching

Sometimes teachers show a problem and then demonstrate to the class how to solve it. They believe that they can just transfer their own thinking into the student’s head through an explanation. Unfortunately, for new ideas, a brain doesn’t work that way. Unless the brain actively constructs those ideas within, it is as if the material was never heard.

“Never learned in that way!! Maybe some of us who might become teachers one day will benefit from videos like this…”

– Nikhil lekhra cREATIONS


Classroom exercise


Do you think active learning could also work in your class? Why not try it out!

Split your class into several groups and assign a new topic to each that will be covered on the next test. Each group will have to make a detailed mind map of the topic and present it at the next class. The level of detail covered and the complexity of the mind map can be adapted to fit the level of your class. Make sure you thoroughly instruct your groups on how to make a mind map before you start. Address the mind map on the next lesson where you explain the topic and review the information the students collected. This should give your students a good foundation in mind mapping and give them a stock of relevant mindmaps for revision, all the while actively adapting their brains to the new information. Let us know how it goes in the comments below 🙂

You can also do this on your own as a student!

For more ideas on how to incorporate active learning into your teaching or learning, check out this link .