What Are Spacing and Interleaving?
If you’ve studied education, you might be familiar with the concept of "spacing." It suggests that to spread teaching or reinforcement activities over time increases retention and performance better than teaching the material all at once and move on.
One example is teaching vocabulary in a foreign language class. If you present and drill 10 new words during a one-hour class, recall at the end of the class will be high, but retention and performance over time will be poor. But if you present the vocabulary, wait 48 hours and review and practice, wait another 48 hours and do it again, etc., retention and performance will increase significantly.
This is a powerful and proven technique that's been largely unused in corporate education. Most training programs, whether online or classroom-based, present material in a linear fashion and don’t circle back to reinforce. If a program includes a practice session, that session typically follows the instruction. It seeks to produce immediate performance rather than long-term retention and performance.
A corollary concept is interleaving; this is similar to spacing, but taken a step further. With interleaving, you break instruction or reinforcement into smaller sections and weave them together, rather than present each one completely before moving to the next. So instead of teaching all of topic A, then all of topic B, then all of topic C, you teach the first part of topic A, then the first part of topic B, then the first part of topic C, before returning to teach the second part of topic A, the second part of topic B, and so on.
You can also use interleaving very powerfully for practice and performance. For example, you cover the full topic today, followed by a practice exercise. Then you move to the next items on the syllabus. But halfway through the next instruction, you take five minutes to return to the previous topic and conduct another performance exercise. So the exercise is spaced, but you’re also intentionally allowing the student to shift gears to a new topic before being forced to return to a previous topic and recall learning.
So, how can we incorporate spacing and interleaving into corporate learning design—and particularly online, self-directed learning? Here’s an example. Let's say we’re teaching sales reps about a new product. A standard, linear syllabus may look like this:
The new Widget 9300: What it is
The target market for the Widget 9300
Features and benefits of the Widget 9300
Handling objections when presenting the Widget 9300
If we use interleaving, we might structure the presentation like this:
A. Presenting the Widget 9300 to target market 1:
1. Who target market 1 is
2. How to introduce the Widget 9300 to target market 1
3. Features and benefits for target market 1
4. Handling likely objections from target market 1
B. Presenting the Widget 9300 to target market 2:
1. Who target market 2 is
2. How to introduce the Widget 9300 to target market 2
3. Features and benefits for target market 2
4. Handling likely objections from target market 2
Then "Presenting the Widget 9300 to target market 3" and so on.
If the class covers other products, you can further interleave by teaching about one product for a while, then switching to a second product, then a third, and then circling back to the first product for further instruction. In this way, you can also compare and contrast products, or ask students to consider a prospective client and choose among the features of all the products to determine which would be most beneficial to the client—further enhancing learning and performance.
True spacing can be more challenging in the corporate classroom because we’re often time-limited. Ideally, the interval between instruction should be just short of the amount of time it will take the student to forget the last instruction on the topic. But since it’s almost impossible to determine when students are about to forget, most of the time we’re using 24- or 48-hour intervals.
So if you’re conducting a four-hour class, you probably won’t have access to the student a day or two later to conduct the first interval session, let alone reinforce multiple times at one- or two-day intervals. But perhaps you should. Maybe your course design should require that students return to the class for 20 minutes every other day for two weeks for follow-on training.
Email is another option. Every other day, students might receive an email from the instructor with a few paragraphs of re-instruction, followed by a set of questions they must complete and return by email.
Online learning offers other possibilities for interval instruction, since you can require the course to be taken in short increments over multiple days or weeks. For example, you could structure it in twelve 10-minute modules, with one to be completed each Monday, Wednesday and Friday for four weeks. That builds in spacing and lets you interleave topics and reinforce with spaced performance exercises.
Have you tried to build spacing or interleaving into your training programs? Tell us about it. If you haven’t, do you plan on giving it a try? We’d love to hear your thoughts.