Spaced repetition: to learn more in less time.

There are fundamental differences in how brains and computers process and store information. Computers store whatever information they are told to store. The brain, however, is something we have very little direct control over. We have no more direct control over how much of a textbook we can remember. The second major difference between the brain and a computer is in how information is processed. It’s tempting to think our memories are stored as discrete “files” somewhere in the brain. We might imagine that when we remember an event in our lives, or a piece of information we studied, we’re “opening” that file. But science tells us this isn’t true. A “memory” doesn’t exist in any one place in the brain, but is an emergent feature of many different parts of the brain firing in a certain way. When we learn something, it isn’t stored in a single location, but is instantly scattered across many different regions of the brain. Finally, the brain has limitations that are, at least for now, impossible to overcome. Studies have consistently shown that we can only remember five to seven new pieces of information at a time. It’s fascinating research, but it also has practical implications for how we should learn. Any effective approach to learning has to be developed with the brain’s inherent limitations in mind. Similarly, we know that the brain preferentially stores information it deems to be important. It strengthens and consolidates memories of things it encounters regularly and frequently. So spaced repetition makes a lot of sense. Spaced repetition is simple, but highly effective because it deliberately hacks the way your brain works. It forces learning to be effortful, and like muscles, the brain responds to that stimulus by strengthening the connections between nerve cells. By spacing the intervals out, you are further exercising these connections each time. It produces long-term, durable retention of knowledge. The way we think about health has been revolutionized by our growing evidence of how the body works. Yet the way most of us approach learning remains the same as it has for centuries. Spaced repetition is just one of the ways we can become evidence-based learners, allowing us to learn more in less time.