If we focus on practising only one thing for an extended period of time, the learning effect tails off. The solution to this is to interleave different skills, topics or concepts within a practice session.
This is in contrast to blocking, which is repeatedly practising one thing over and over again. For example, practising the same phrase on the piano until you can play it fluently.
The evidence suggests that interleaving improves the development of skill or knowledge. For example, studying different aspects of a topic or related topics, rather than just one topic; or practising a variety of different phrases on the piano during one practice session.
If you need to practice three things (‘A’, ‘B’ and ‘C’) the pattern ABC-ABC-ABC is likely to be more effective than AAA-BBB-CCC.
There are caveats:
- The evidence is still a bit sketchy.
- There is some evidence that interleaving can be detrimental for learners who are complete novices. Presumably because they don’t have yet have well-developed mental models, so the different elements get confused.
There are two theories as to why interleaving works:
- Blocking allows you to fall into automaticity. With interleaving, each practice attempt is different from the last, so the brain has to work to generate solutions. This strengthens memory.
- With blocking, you only need to come up with one solution, which can be held in working memory between attempts. With interleaving, you need to retrieve the information from long-term memory every time, which strengthens neural connections, building memory.