WHY SPACING WORKS
Is acing a test a sign of mastery? You learned the concepts, you’ve honed the skill, so that must mean you’ve mastered it, right? Not quite.
While passing a test is a great indicator of performance or study habits, it doesn’t actually say anything about a student’s ability to apply the knowledge that they’ve learned or even to remember it correctly beyond the exam day.
Part of this has to do with the way that humans learn. Reviewing and re-reviewing mountains of information the night before a big test might help you pass, but you are unlikely to retain much of what you learned in the long run. What’s more, as you try to consume the maximum amount of information over a short period of time, it’s inevitable that small, important details will be lost.
Spacing promotes long-term retention by spreading learning out into manageable portions over time. One study found that spacing study sessions out by days or even months improves retention. As learning scientist Yana Weinstein-Jones says “spacing enables additional opportunities to retrieve or remember that information…in order to stop the forgetting process”
It’s now conventional wisdom that “cramming” is bad. That’s supported by research: gaps in studying promote long-term retention while cramming simply does not.
What Is Spacing and Why Does It Work?
Contrary to what you might think, spacing is not a new or trendy subject. Identified by a 17th-century German psychologist, shaping has been studied for centuries to better understand why and how humans learn the way we do.
Directly related to retrieval—consciously recalling stored knowledge—spacing involves reviewing information over a period of time, rather than all at once. Spacing gives your brain time to consolidate new information so it’s easier to retrieve it when necessary.
Imagine two actors need to learn lines in a play. One actor sits down and memorizes all of his lines at once. The other learns the lines from each scene over the course of a week, reviewing old lines and new as necessary. Whose strategy will likely be most successful?
Cramming is deceptive. It might seem more time-efficient to study for a mid-term all in one night or weekend, rather than over 5 or 6 weeks in between tests. In the end, though, you will end up spending the same amount of time studying with less payoff.
To understand why that is, you need to first understand the forgetting curve, which posits that retention of a memory decreases over time. That’s simple enough but what does that look like in practice?
Think of last time you went to a big event with lots of unfamiliar faces. Of the people you met, how many names can you recall now? How many could you recall at the end of the night?
The forgetting curve suggests that if you meet a guy named Sam in passing, chances are, you will forget that name within a few hours, if not minutes. But what if you run into Sam again later that that will jostle his name in your memory, and you will remember it a bit longer. If you make an active effort to remember his name after meeting, you’re unlikely to forget it.
In other words, the forgetting curve exists, but it can be combated with spacing.
Spacing practice allows you to recall information you learned earlier, like Sam’s name, keeping it in your memory longer. The key to successful spacing is to repeat this process of actively remembering things before you have a chance to forget them.
Retrieving knowledge that is on the margins of your memory, requires more mental work than accessing newly-acquired knowledge. But that extra work ensures that your brain will hold on to it longer. Spacing is effective because each time you revisit old knowledge after a period of time, you shift the forgetting curve out a little further.
There are many ways for teachers to incorporate spacing into their regular classroom lesson. One simple way to do that is to shift from two or three big exams each semester to more frequent, lower stakes exams. Students will revisit the material more regularly throughout the semester increasing their retention of what they have already learned. It can also cut down on ineffective cramming practices, because the more students routinely revisit and strengthen, the less there is for them to cram.
Some other ways to organically incorporate spacing into the classroom are mixing older material into tests and doing short reviews of previous lessons at the start of class.
Two teachers at Medomak Valley High School in Maine have experimented with spacing in their classrooms. Bill Hinkley and Heather Webster have both adapted spacing strategies to help improve student learning. Heather noted that, “my expectations were really high for what they should be able to retrieve, or what they would remember…(I) try to get into the kids’ perspective a little bit…how is their brain processing the information that I’m saying?”
It can be easy to forget when you’ve resurfaced and practiced knowledge consistently over the years to the point of expertise but for those who are still learning, recall won’t be as easy. If students are not revisiting materials regularly, it’s not a question of if they will forget but when. “I find it to be a relief knowing that…we just have to keep hitting it time and time again,” Heather added.
What is the optimal amount of time to space out review? There’s no exact answer to that. It will vary based on how many times a topic has been revisited and The fact is that any spacing is better than none. However, the best time for students to review something, seems to be right before they forget it.
With this in mind, Bill restructured his class to push review upfront, starting each lesson with a review of the old before starting the new. By challenging his students to recall that old knowledge, Bill’s practice helps them resurface what they remember and reminds them of what they do not.
Spacing in Action
A perfect example of successful spacing in the real world is Roger Craig. Craig was fond of games since childhood and particularly loved Jeopardy. He was toying with the idea of trying out for the game show, when he came across an article that changed the way he thought about learning. The article, published in Wired magazine, highlighted the effectiveness and precision of spacing, all backed up by science. That stuck with him.
Without realizing it, Craig had been using spacing to study more effectively, even creating a computer program to regularly resurface old material before he had a chance to forget. Now, he had discovered that strategic spacing could unlock the door to a more advanced way of learning—and maybe also his Jeopardy dreams.
Armed with this new knowledge and the spacing-based online software Anki, Craig used an intense spacing method to review a database of Jeopardy questions. As he reviewed topics, they were prioritized based on the rate at which he forgot them. For example, if Craig mixed up a fact about the French Revolution, then a few minutes later, he would get another question related to the French Revolution. Once he got the correct answer, that topic wouldn’t be resurfaced again for a few days, and then a few months, and so on as he shifted his forgetting curve back more and more with each revisit.
His hard work paid off. Craig appeared on Jeopardy in 2010 and blew away his competition, barely missing a single question. By the shows’ end, Craig broke Ken Jennings’ record for most money won in a single game. What’s more, he returned and won the game six more times, setting the record for five-day winnings, before excelling in the Tournament of Champions.
Craig initially thought his remarkable win was a fluke. In retrospect, he now attributes his success to spacing. As he told NPR, “Everybody that wants to succeed at a game is going to practice at the game…You can practice haphazardly, or you can practice efficiently. And that’s what I did.”
School: Medomak Valley High School, Medomak, Maine
Teachers: Bill Hinkley, Heather Webster
Researcher: Dr. Yana Weinstein-Jones
Author: Ulrich Boser