Interleaving: a teaching and learning method for better long-term results

Interleaving is a highly effective learning and teaching strategy, which means it can be applied by both students at home and teachers in class. It involves distributing practice of a topic over time, as well as mixing up the order of materials studied across different topics. For example, three hours of learning three separate topics one after the other are transformed into six 30-minute sessions, alternating the different subjects.

The benefits of this method stem from two other learning strategies, the first of which is spaced practice, otherwise known as the opposite of cramming, which essentially means studying more often, but for shorter intervals. The second is retrieval practice, which involves deliberately calling information to mind that has been previously stored in long-term memory in order to enhance learning.
Whether at home or in class, asking students to regularly recall recently acquired knowledge allows them to create various recall pathways to that information while connecting it to other prior knowledge, further strengthening those memories so they will last longer.

Interleaving may seem harder or less useful than simply studying one subject at a time during longer and uninterrupted sessions, but switching from one subject to another combines the memory advantages of both spaced practice and retrieval practice to improve the creation of long-lasting memories. Though we may feel like we remember more after focusing on a single topic for an extended period of time than we do after alternating subjects during that time, the long-term benefits of the latter far outweigh the short-term benefits of the former.

As usual, there a couple of things to keep in mind.
First, it is important not to switch between subjects too much or have intervals that are too short. Twenty to thirty-minute blocks are probably the shortest to use, or you risk suffering the negative aspects of multitasking.
In addition, being efficient in the transitions between study sessions that are interleaved is key, otherwise much time can be lost in the process. As a learning strategy, it requires good planning and organisation; as a teaching strategy, the sequence of topics or subjects must be designed depending on the material and the way the different elements can build on each other. Though the topics of an interleaving session can cover different subjects, some experts believe the strategy is most efficient when the subjects are related in some way.

Interleaving is more complicated and counterintuitive than spaced and retrieval practice, but as is the case for these other two strategies, its aim is not to facilitate studying, but to help students remember and understand things more easily in the long run.

Content drawn from “The Science of Learning — What Every Teacher Should Know”, EdX: https://www.edx.org