Interleaving

To interleave means to weave together or mix. Instead of twenty math problems of the same kind, you practice different kinds taking turns. It is like soccer practice where passing, shooting and dribbling come up all mixed together, just like later in a real game.

In 2007 Doug Rohrer and Kelli Taylor in the USA had students practice math problems. One group did the problems sorted by type, the other mixed. During practice the sorted group did better. But on the test a week later, the mixed group was clearly ahead. A year later Nate Kornell and Robert Bjork showed something similar with paintings: people learned the painting styles better when mixed, but believed themselves that sorted had been better.

When everything looks the same, your head switches to autopilot. With mixing, you have to think again each time: what is this actually, and what goes with it? That is exactly the telling-apart you need later, when nobody tells you what kind of problem you are looking at.

The Feed in Mnemorya mixes cards from different topics that are due at about the same time. So you don't get one topic in one go, but a colorful mix, without having to sort anything yourself.