Spaced Practice for Skill Learning

Spaced Practice for Skill Learning

By Cindy Nebel

Psychologists often breakdown memory into different types. Long-term memory can be divided into two different types: explicit memories and implicit memories. Explicit memories are memories for events and facts. They are memories that we can easily think and talk about. Implicit memories are a bit different. Implicit memories include procedural (muscle) memories as well as some other types of automatic processing.

The primary focus of most of the things on our site is the acquisition and retention of factual information, which would fall into the explicit memory category. When we talk about spaced practice, we often talk about studying in small sessions over the course of time instead of studying in one long session.

Sometimes when we talk about the six strategies for effective learning, we get a little push-back from educators who state that they don’t want their students to simply memorize information, but to understand it. Thankfully, the six strategies do promote understanding. We also sometimes hear that we are talking about learning facts, but that is not useful in other areas, such as art. But again, we’ve talked about the usefulness of the strategies in lots of other subjects (and even for dressage!).

Today I want to talk a little bit more about how we can use one of the strategies, spaced practice, to improve learning of implicit memories – of skills. While teaching a course on Learning last week, I told the students about a classic study showing that spacing works not only for explicit learning, but also for skill learning. Here is that study:

Baddeley and Longman (1) trained postal workers on a new typing task that sorted mail. At the time, this was a very practical matter. Going from hand sorting to mechanical sorting would require training up to 10,000 new postal workers, so doing this in the most efficient way was key. They started out by training 72 workers in sessions that were either 1 or 2 hours long, either 1 or 2 times/day until all of the groups had worked on the training for 60 hours. So the group who training for 1 hour 1 time/day had trained for 60 days, but the group that trained for 2 hours 2 times/day had only trained for 12 days. Note that each group received the same amount of training and that they were paid the same amount to do that training.

Below, you can see the results of part of that study. This shows the number of hours that it took for each group to learn the new typing skill. Those that practiced for 1 hour once/day took considerably fewer hours to learn the new skill than did those who practiced for 2 hours twice/day. In fact, the fastest person in the latter group took 2 hours longer than the slowest person in the former group.