“To teach is to learn twice over.”
—Joseph Joubert
You’ve probably heard the popular saying, “Once taught, twice learned.” The idea is simple: when we teach other people, we reinforce our own learning. But did you know that this idea is not only supported by neuroscience—it’s also the secret weapon behind some of history’s most gifted thinkers?
The idea that teaching others helps us learn has been attributed to many people throughout history. Perhaps the first among them was Roman philosopher and Stoic Seneca the Younger, who said “docendo discimus,” or “by teaching, we learn.” But this isn’t just theoretical. In the modern era, studies have found that the act of teaching causes observable increases in both learning and IQ. Because of this, neuroscientists have sought to understand exactly how this effect works. More importantly, they’ve tried to figure out how we can harness it to our own learning advantage. They’ve studied first-born children, student teachers, and even middle school students in computer teaching simulations.
The results have been both surprising and conclusive: when we teach others, we ourselves benefit tremendously.
But why?
First of all, teaching others is an incredible motivator. The moment we commit to teaching something to someone else, we are compelled to improve our own understanding. Suddenly, we are inspired to serve that person as best we can. Not to mention, we’d like to avoid embarrassing ourselves in the process! This, in effect, harnesses all the benefits of self-testing but makes the stakes real. It’s also why, during the chapter on pre-reading, I suggested imagining how you’d share the information with someone you know.
But far beyond that, teaching a subject to someone who knows less than we do presents unique challenges and opportunities for us as learners. Other people have different learning styles, curiosities, and levels of understanding. Consequently, teaching them requires us to take a more thorough and comprehensive approach to our own learning. It requires that we move higher up in Bloom’s Taxonomy. We’re forced to imagine new and alternative ways to understand a subject. Then, we must create simpler, more creative ways to transmit that understanding to others. This process of dissecting a subject well enough to explain it results in a much deeper understanding among those who teach. As Albert Einstein, who was himself a professor at Princeton, once said on teaching, “If you can’t explain it simply, you don’t understand it well enough.”
Finally, when we teach other people, we are presented with unique questions. These questions are sometimes far outside our own scope of focus. But that doesn’t make them any less crucial to our own understanding. Not long ago, I was chatting with a few friends who had developed an interest in Blockchain technology—a subject I’d spent six months intensely SuperLearning. As such, the first half of the conversation entailed me simplifying the inner-workings of this complex innovation. After about twenty minutes of me pontificating, my friend interjected with a highly specific question. So specific, in fact, that “I don’t know” was an understatement. I had never even thought about that aspect of the technology! I was immediately motivated to go seek out the answer. Once I did, I was able to fill a knowledge gap I would’ve never discovered on my own. This illustrates one of the greatest benefits of teaching: the people we teach unknowingly test us. They give us insights into what we don’t even know we don’t know.
In essence, teaching is a lot like having other people “check your work.” When you teach, you share the information you’ve acquired to the best of your understanding. This isn’t that different from a free writing test, in that it requires plenty of higher-level thinking and understanding. As you teach, you are essentially recruiting other people to look for the holes in your knowledge. When they find those holes, they alert you to the areas you should go back and study further. Best of all, they do this in a much more friendly way than a teacher grading your exam, and they do it completely for free! In fact, if you work it out right, they might even pay you to tutor them!
In my years of teaching online, I’ve come to realize just how powerful it is to have thousands of people highlighting the details I don’t fully understand or haven’t fully considered. Every time someone asks a question in one of my courses, I’m prompted to ask myself if I understand this aspect of the subject well enough to explain it. If I don’t, I’m immediately motivated to do the research and learn about it. In fact, until someone asked me about the effects of teaching and learning, I’d never even thought to check the research behind this learning super-strategy. In this way, I credit my students for a large portion of the content in my flagship SuperLearner MasterClass.
Teaching is such an effective way to learn that I’ll often build entire courses because I want to learn more about the topic myself. This gives me an opportunity to partner up with other experts, download as much of their knowledge as I can, and research whatever else I want to know. Best of all, I get to help students and readers like yourself in the process. Indeed, after mnemonic techniques and speed-reading, teaching has probably had the biggest effect on my ability to learn. I’ve used it to learn everything from Bitcoin to AcroYoga, endocrine health to marketing. This is why, if we ever meet, you’ll probably find me teaching.
This technique was leveraged by many great learners before I was even born. Perhaps best known was Nobel Prize-winning theoretical physicist Dr. Richard Feynman. Feynman had a lifelong passion for teaching, which was evident to anyone who ever met him. Throughout his career, Feynman taught at both Cornell and Caltech. He also advocated for alternative teaching methods at the California State Curriculum Commission and the National Science Teachers Association.
To this day, Feynman is known for his four-step model of learning, which goes like this:
Using this methodology, Feynman became one of the most prominent and respected scientists of all time. He was so much more than a Nobel Prize-winning thought leader in one of the most complex subjects known to man, astrophysics. He was also the author of the most popular series of physics lectures and books ever created, The Feynman Lectures on Physics. This and his passion for teaching earned him the loving nickname “the great explainer.” What’s more, Feynman was a tried-and-true polymath. Throughout his life, he used this technique to master not only physics but everything from lockpicking to languages, bongo drums, and even salsa dancing.
As we near the end of our time together, I’d like to make one humble request: teach those around you what you’ve learned in this book!
One of the best things you can do to reinforce everything you’ve learned about memory and neuroscience is to get out there and teach it to others.
Tell your kids. Tell your friends. Tell your spouse. Tell anyone who is interested how they can use visual mnemonics and things like the memory palace to learn anything faster. Not only will you be doing them a great service by exposing them to this life-changing field, but you’ll also benefit a great deal for all the reasons mentioned above. You might not be a perfect teacher. You might even be new to teaching. But if you’ve made it this far, you’re more than qualified to share these lessons with your friends and family. And if they want to learn more, or they drive you crazy with their questions, send them to http://jle.vi/book, where they can claim a free copy of this book for themselves!