Interleaving: Being Mixed Up

Practice makes perfect, right? Kind of--but it takes the right kind of practice, something known as interleaving. Most of us are familiar with the usual "other" type: if we want to "master" the free throw, for example, we might take 300 shots in a row, until it gets dark, or our arms feel about to fall off.

Yet an 1978 experiment from the University of Ottawa involving 8-year-olds and bean bags demonstrated, practicing one thing successfully does not necessarily lead to transfer in a real situation. One group practiced throwing bean bags into a target from two and four feet. The other group practiced only at 3 feet. When the final test was conducted at three feet, the group that practiced only at two and four feet actually did much better. 

Another study in 1986 from Louisiana State University studied how women players practiced three types of badminton serves. Group A performed blocked practice, rehearsing only one type of serve each session. Group B performed serial practice of the three serves. Group C did random practice of the three serves. After three weeks, group C (random) performed best, followed by the group B (serial), while group A (blocked) was the worst.

In 2007, at the University of South Florida, 24 grade 4 students had to calculate the number of faces, edges, corners and angles in a prism. Half the students learned in a blocked format, while the other half did the exact same problems but randomly. Results: the mixed-study group outperformed 77 to 38 percent.

Particularly in math word problems, the greatest challenge for students is in selecting the right strategy or algorithm needed. Therefore,  mixed or random studying will give students the greatest amount of real practice necessary when they encounter a variety of questions and problems.   

Repetition appears to show rapid improvement but then it plateaus. Varied practice, on the other hand, seems to show slower improvement but the results are a greater accumulation of skill and learning. 

Here is where interleaving is so important to practice. It is the mixing related but distinct material during study. It works for pretty much all areas of learning: skateboarding, playing an instrument, cooking, algebra, art. Shorter breaks of different but related activities will achieve the most success, about 10-15 minutes each.

Real life is not so cut and dried, and you need to be able to recall a variety of facts, information and skills in order to solve real-life problems. Having experience in doing many different types of tasks will lead to the greatest amount of transfer of learning. 

Source: How We Learn, Carey