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Memory

Your Brain Was Built to Forget—Make It Work For You

Harness the science of forgetting and interleaving to think more clearly.

Key points

  • Forgetting isn’t a bug; it’s the main feature with which the brain refines memory and finds meaning.
  • Curious minds forget more because they explore more. Strategic forgetting is a feature and a feat, not a flaw.
  • Interleaving strengthens memory by mixing topics, mimicking how we face problems in real life.
Aleshyn_Andrei/Shutterstock
Source: Aleshyn_Andrei/Shutterstock

Forgetting things is a blessing, believe it or not.

For proof, imagine a world where every detail you ever came across was etched indelibly in your mind. Every conversation you regret, every rejection you've ever felt, every time you stepped out with your zipper undone, stands as clearly in your mind as what you had for breakfast last week, as well as the moments that bring you the greatest joy. That is a world of utter chaos and misery.

We don’t need to stick to just our armchair-philosophizing, however. Thanks to the wonderful combinatory magic genetics pulls off at each birth, we've had a few individuals on Earth who are unable to forget anything.

Solomon Shereshevsky, a Russian mnemonist famously studied by neuropsychologist Alexander Luria, could memorize lists of arbitrary numbers, words, and nonsense syllables with perfect recall, even decades later. More recently, people with hyperthymesia, like Australian woman Rebecca Sharrock, report being unable to forget even the most mundane details of their daily lives.

At first glance, this sounds like a superpower. But many of them describe it as exhausting, distracting, and emotionally overwhelming. As Rebecca puts it: “Most have called it a gift, but I call it a burden. I run my entire life through my head every day, and it drives me crazy.”

Why It's Good to Forget

What most miss about forgetting is that it is not a design flaw. It’s a feature.

The ability to forget is fundamental to learning. It’s what gives us focus, highlights the signal through the noise, and lets the brain determine what matters most, given the context we are in.

Research suggests that forgetting is an active process involving brain regions like the hippocampus and prefrontal cortex (Davis & Zhong, 2017), which help us manage the inflow and outflow of information. Forgetting is not our memory failing on us as much as it is our memory being optimized.

And here is where we meet the wonderfully counterintuitive concept of the forgetting curve. First described by Hermann Ebbinghaus in the late 19th century, whose self-tests on memorization are sure to spark an insight or two in modern readers alike, the forgetting curve tracks how quickly we lose information over time without reinforcement.

Within hours of learning something new, we begin to forget it. Rapidly at first, then more slowly over time. The key insight of those who have followed Ebbinghaus is that this curve is not fixed. On the contrary, it’s something we can reshape, a feature we can tune ourselves.

How Interleaving Can Help You Learn

One such way is the practice of interleaving. In memory studies, interleaving is the act of mixing different topics or types of problems during study or practice sessions, rather than focusing on one subject at a time (a method known as blocking).

Think of it as cross-training for your brain. Instead of grinding through a single skill or topic, you jump between them—math, history, language, coding—and in doing so, your brain becomes better at remembering each one.

Studies have repeatedly shown that interleaving improves long-term retention and the transfer of knowledge. For example, a 2008 study by Rohrer and Taylor found that students who practiced math problems using interleaved methods scored significantly higher on later tests than those who used traditional blocked practice. Interleaving creates “desirable difficulty,” where it all feels harder in the moment, but it leads to stronger memory traces and better pattern recognition.

One reason why interleaving works is because of how closely it mirrors the way our brains encounter problems in real life. Life doesn’t present challenges in neat categories, nor does it present them for us to learn eight hours at a time with a toilet break and lunch in between. Your brain is desperate for learning experiences that allow it to recognize patterns, discriminate between concepts, and choose the right tool without a neatly labeled folder.

And perhaps more philosophically: Interleaving works because forgetting works.

When you return to a concept you’ve almost, but not quite, forgotten, you have to work harder to retrieve it. That retrieval strengthens the memory, encoding it more deeply. It’s as if forgetting creates the tension that learning needs to settle into place. Like tuning a guitar string, the right amount of stretch gives our concept neurons the right resonance to restart the forgetting curve at a higher level while leaving it with a more gradual slope with more retained at the end.

How to Forget Better

What does all of this mean for the curious mind?

It means we should spend less time obsessing over learning more and more time thinking about how we forget better. We should design our study routines, and even our daily lives, around spacing, switching, and revisiting ideas over time.

Interleave reading with conversation. Interleave watching with writing. Interleave passive input with active recall. Play five minutes on the piano between two hours spent on your midterms.

And most of all, we should stop treating forgetting as failure.

If you’re curious about many things, if you’re constantly exploring, dipping into new ideas, and then moving on, you’ll forget a lot. Good. That’s the point. The brightest minds often forget more than others have ever learned because they are in constant motion.

Let’s not mistake accumulation for wisdom. Let’s not measure memory by what stays lodged in the mind but by how effectively we can return to what matters. Learning is not a warehouse, and the brain is not a hoarder.

Instead, the act of learning is a dance where we should expect to miss a step or two. And forgetting, when properly understood, is the drumbeat that keeps the rhythm.

So yes, this is your cue for embracing your inner goldfish. But make it strategic. Use interleaving to let your curiosity breathe, jump, stretch, and explore places that you can happily forget later on.

Let forgetting be your superpower. And never be afraid to forget a truth so that you can feel the joy of rediscovering it all over again.

References

Luria, A. R. (1968). The Mind of a Mnemonist: A Little Book About a Vast Memory. Harvard University Press.

Bjork, R. A., & Bjork, E. L. (1992). A new theory of disuse and an old theory of stimulus fluctuation. From Learning Processes to Cognitive Processes: Essays in Honor of William K. Estes, Vol. 2.

Brown, P. C., Roediger, H. L., & McDaniel, M. A. (2014). Make It Stick: The Science of Successful Learning. Harvard University Press.

Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis.

Kornell, N., & Bjork, R. A. (2008). Learning concepts and categories: Is spacing the "enemy of induction"? Psychological Science, 19(6), 585–592.

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