The influence of working memory capacity and material complexity on the testing effect

Introduction This study investigated how working memory capacity and learning-material complexity influence the testing effect and explored strategies to improve learning outcomes for learners with low working memory capacity studying complex materials. Methods Four experiments involving fourth-grade primary school students were conducted. Experiments 1a and 1b compared retrieval practice with restudy among learners with high and low working memory capacities using low- and high-complexity materials, respectively. Experiment 2 examined repeated retrieval practice under equally spaced and expanding interval schedules. Experiment 3 examined diminishing-cues retrieval practice. Results For low-complexity materials, learners with low working memory capacity performed significantly better following retrieval practice than restudy. For high-complexity materials, this advantage emerged among learners with high working memory capacity. Among learners with low working memory capacity studying complex materials, both repeated-retrieval schedules in Experiment 2 improved post-test performance relative to restudy. In Experiment 3, diminishing-cues retrieval practice outperformed both cue-free retrieval practice and restudy. Discussion The findings suggest that material complexity moderates the relationship between working memory capacity and the testing effect. Repeated retrieval practice under the schedules tested and diminishing-cues retrieval practice may support learners with low working memory capacity when studying complex materials.