True Mastery: The Benefits of Mixed Practice for Learning

“Practice, practice, practice.” This mantra for learning is proclaimed across companies and schools, athletics and the arts. The widely held belief is that the key to mastering a particular skill or gaining new knowledge is relatively straightforward: Practice. 

Now, to be sure, practice is important, especially if it rises to the threshold of “deliberate practice,” an intensive approach which Patrick lucidly explained in a past article. He himself warns, however, that the repeated rehearsal of skills can be futile if the three other components of deliberate practice are not in play. Patrick writes,

“ We need to be careful with this first component. It is all too easy to set up high frequency and think we are accomplishing something, when in fact all we are doing is a long series of empty work.”

Here it is acknowledged that merely bumping up the frequency of practice is not enough to hone a skill or understand a concept, particularly complex ones that are multifaceted and layered.

Applying this to the classroom, what can be done to ensure that the sort of practice our students engage in is not wasted? From differentiating between direct and indirect objects to solving algebraic equations to writing thoughtful, well-developed essays, how can we train our students in such a way that the skills they develop and knowledge they gain remain in their memories long-term? 

The Myth of Massed Practice

In Make It Stick: The Science of Successful Learning, authors Peter Brown, Henry Roediger, and Mark McDaniel propose that one of the keys for long-term, strong and flexible mastery of a skill or concept is to mix up the practice. But first they dispose of the myth of massed practice. Massed practice is the focused, repetitive practice of one thing at a time until it is mastered (47). To be fair, this approach to learning is fairly intuitive and therefore enjoys quite a bit of trust from onlookers and practitioners alike. For example, the common advice for increasing one’s free-throw percentage in basketball is to shoot over and over again from the fifteen-foot mark (the distance from the free-throw line to the hoop). For those of us with basketball experience, we can even testify to the success of this strategy, specifically how quickly we experienced gains by utilizing this method. 

But real learning, insists the authors of Make It Stick, includes more than how quickly the skill is mastered or knowledge is acquired. What matters even more is whether that skill or knowledge is accessible to our memories when it is needed later:

“The rapid gains produced by massed practice are often evident, but the rapid forgetting is often not” (47).

The litmus test for successfully learning a skill, then, is whether this practical knowledge remains in our memory long-term. Scientists call the increased performance during the acquisition phase of a skill “momentary strength” and distinguish it from “underlying habit strength” (63). 

I have experienced this distinction between momentary strength and underlying habit strength too often in my ongoing development as a handyman. Thanks to the internet, when something in my house needs fixing or replacing, I need only search for the relevant video online to find out how to solve the problem. After watching the video (ten times over) and then completing the job myself, I gained momentary strength in the skill. I walked away from the project feeling confidently handy. However, three months later, when the same problem returned, I discovered that in the previous experience I had not actually gained underlying habit strength. As I scanned my memory for knowledge and proficiency of the skill, the search results were clear: no records found. (Note: I suppose I am exaggerating. My memory could recall some bits and pieces of what I had learned previously. But it wasn’t nearly sufficient for what I need to fix the problem again. Too much had been lost.)

Why? I had used massed practice, developing momentary strength, but not underlying habit strength that would serve me well long-term. I watched the video, spent a focused, inordinate amount of time honing the skill, and then neglected to practice it for three-months. Over this duration of time, the practical knowledge I gained was lost. It faded away into the distance, along with other short-term memories, like what I wore to work that day or what I had for breakfast.

So failing to gain long-term retention is one problem with massed practice, but even worse, this approach to learning, according to researchers, generally leads to inflexible, surface-level comprehension that is not amenable for complex cognitive acts like differentiation and application. In other words, it doesn’t lead to true mastery. 

Three Ways to Mix it Up

In order to reach this level of true mastery, mixing up the practice is the way to go. And, according to the latest research, there are three main ways to do so: 

1. Spaced Practice: Instead of intensively focusing on one skill for a single, extended session, space out the practice into multiple sessions. Work on it for a while and then return to it the next day or week. The space allotted between each session allows for the knowledge of the skill to soak into one’s long-term memory and connect to prior knowledge. Revisiting the skill each session certainly takes more effort, but that’s the point:

“The increased effort required to retrieve the learning after a little forgetting has the effect of retriggering consolidation, further strengthening memory” (49).

2. Interleaved Practice: While we experience the quickest gains by focusing on one specific skill or subset of knowledge over a period of time (momentary strength), interleaving, or mixing up the skill or concept you are focusing on in a practice session, leads to stronger understanding and retention (underlying habit strength). It feels sluggish and frustrating at times, for both teachers and students mind you, because it involves moving from skill to skill before full mastery is attained, but it leads to both a depth and durability of knowledge that massed practice does not (50).

3. Varied Practice: Varying practice entails constantly changing up the situation or conditions in which the skill or concept is being applied. It therefore strengthens the ability to transfer learning from one situation and apply it to another, requiring the student to constantly be assessing context and bridging concepts. Because this jump from concept to concept triggers different parts of the brain, it is more cognitively challenging, and therefore encodes the learning “…in a more flexible representation that can be applied more broadly” (52).

Test Case: Mixed Practice in Math Class

Let’s apply this concept of mixed practice to math class. The teacher is explaining to her students how to calculate the volume of geometric figures. The “massed practice” approach would have her teach the formula for calculating the volume of, say, a cube and then release her students to find the volume for ten different sized cubes. By the end of the class period, the majority of her students would be comfortable performing the algorithm, thereby demonstrating ostensible mastery of the skill (at least in the short-term).

Contrast this scenario with the “mixed practice” approach. The teacher might start by teaching the formula for the volume of a cube and then giving her students a couple practice problems to solve. But soon after, she would teach a different formula, say, the formula for finding the volume of a cylinder and, after that, a sphere. Upon giving her students a couple practice problems for each type of figure, she would instruct her students to complete a set of problems, in which various volume problems are interleaved. This problem set would force students to practice discernment: identify the particular figure, recall the relevant algorithm, and then run the numbers. Periodically, over the following days and weeks, the teacher would include various volume problems in the class warm-up and in the daily homework as well as other concepts previously covered.

As you can see from this example from math class, when mixed practice is implemented, underlying habit strength is forged. The order and types of exercises don’t permit a student to fall into mindless, rote practice. Instead, each problem requires higher level thinking skills beyond memorization such as categorization and application. In order to gain true mastery, the research is clear: mix up the practice. 

Mixed Practice and the Liberal Arts

Let me leave readers with one final thought: I’ve been using the modern phrase “true mastery” as shorthand for the sort of breadth and depth of learning we are aiming for at our schools and in our homes. But I could just as easily describe this outcome using language from the liberal arts tradition. When students engage in the challenge and rigor of mixed practice, they are being trained to learn and think for themselves, to engage in a form of self-education, which is a central idea in the classical tradition (as Jason explained so eloquently in his recent article for Circe). Their tools of learning, the liberal arts, are being sharpened, so to speak.

In addition, by providing opportunities for our students to engage in mixed practice, we avoid teaching them bad habits of cramming, that is, surface-level mastery for brief demonstration on an upcoming test. Instead we give them an opportunity to perform dynamic and valuable work, stretching their minds in flexibility, durability, and discernment, all of which is befitting of their God-given intellects and capabilities.

This is the sort of learning I get excited about and hopefully through this blog more parents and teachers can join us at Educational Renaissance in this life-giving work.