On learning - Distributed practice

tldr: Aim for frequent, manageable study sessions (< 90min). Practice a variety of problems at a time rather than grinding the same ones over and over.

You may not feel like you’re learning as much in the moment, but studies show you’ll gain a deeper understanding this way.

When you have limited time and energy for learning, it’s vital you spend it efficiently. Let’s dig into how distributed and interleaved practice can help.

Working and Long-Term Memory

Your memory works like a computer’s memory - both have systems for short- and long-term storage. A computer has RAM for short-term access to data and a storage drive for long-term storage. RAM stores a small amount of data, but can access it quickly. Storage can hold much more data, but is slower to access. Each piece of hardware performs different roles and is essential for the computer to work.

RAM is analogous to your working memory and can only hold a few pieces of information that you’re focused on. Storage is analogous to your long-term memory.

Memory consolidation is how your brain creates long-term memories. Consolidation happens through repetition and rest. By spreading out practice over time, and mixing problem types in each practice session, you can increase the depth and retention of your learning - or improve memory consolidation.

Effective practice

Memory consolidation requires both repetition and rest. So, study and practice should be spread out over time. This is distributed practice and is the opposite of massed practice (e.g. cramming 4 hours the night before a test).

Structuring practice sessions

Aim to practice long enough to get deep into a topic, without exhausting yourself. 60-90 minute sessions are a good starting point, but you can adjust it for your situation. You probably shouldn’t practice longer than 90 minutes in a single stretch.

Organize sessions throughout the week, according to your schedule. 30 minutes Monday, Wednesday, and Friday is better than 90 minutes on Saturday. It gives your brain time to rest and consolidate memory between sessions.

Take breaks

Take breaks during your study sessions (see the Pomodoro technique), as well as between sessions. Benny Lewis, a prominent language ‘hacker’, describes how he builds a rhythm of breaks into his study.

• Each week, he’ll study 6 days and rest 1 day
• Each month, he’ll take a 2-3 day break
• etc.

Allow yourself adequate rest at the micro and macro level of your study. This pattern of focused work and rest helps you learn. Getting good sleep and exercising will also help.

Interleaved practice

Typically, we practice by doing a similar task over and over. When learning the piano, you might play the same scale for 15 minutes in a row, then you would move on to practicing a song. This is called blocking or massed practice.

Interleaved practice takes the opposite approach. Instead of practice tasks A and B like AAABBB, you would alternate practicing each task more frequently - ABABAB.

In a recent study, college students were divided into two groups to study algebra. Students who did blocked (or massed) practice performed better during practice, BUT when it came time to take a test, the group who did interleaved practice performed better.

This suggests that interleaving practice leads to better retention whereas massed practice gives the temporary illusion of mastery.

Why does this work? Although interleaved practice is still being explored, there are two reasons I think it’s effective.

1. Interleaving forces you to distinguish which technique to use.

When performing massed practice, like integrating trig functions for 1 hour, you tend to get into auto-pilot. The problems don’t vary enough to require much critical thinking. You know what techniques to use and roughly how to solve each problem.

But, if you’re switching between different types of integrals each problem, you have to think deeply about how to solve each problem. Although this makes practice harder, you learn more deeply.

2. Interleaving improves memory

During massed practice, you’re able to hold the majority of info required in your working memory. But with interleaving, each problem will require your mind to clear its working memory and access other information. By repeatedly accessing information from your long-term memory, your brain will strengthen the neural pathways storing the techniques you’re using.

This repetition signals to your brain that the memory it’s accessing in long-term memory is important and helps it know where it’s stored. This form of study increases the reps your brain is getting in recalling different pieces of information and will help you quickly recall that information in the future.

Summary

Spread out your practice over time (distributed practice), take breaks, and practice a variety of related skills or concepts when your practice (interleaved practice).

Happy learning! 🧪