The relationship between interleaving and variability effects: a cognitive load theory perspective

The interleaving effect indicates that students learn better from multiple areas that are interleaved rather than blocked. Two experiments tested the hypothesis that the effect is because interleaving facilitates comparisons between areas and is a variation of the variability effect that increases intrinsic cognitive load. Experiment 1 used an interleaved design with two obviously different topics and found no interleaving effect. Experiment 2 used a similar design but used topics that were more difficult to discriminate between, resulting in a clear advantage for the interleaved group associated with an increase in cognitive load. These results support the hypothesis that the interleaving and variability effects are closely related.