Material Complexity Moderates How Working Memory Capacity Affects the Testing Effect

Fourth-grade primary school students demonstrated differing benefits from retrieval practice depending on both the complexity of learning materials and their working memory capacity, according to four experiments evaluating the testing effect. The experimental results indicated that learning material complexity moderates the relationship between working memory capacity and the performance advantages gained from retrieval practice compared to restudying.

The research, conducted by investigators at Hengyang Normal University and Liaoning Normal University School of Psychology, examined the interplay between student working memory capacity and learning-material complexity. In addition to testing standard retrieval practice, the researchers evaluated specific instructional strategies designed to enhance learning outcomes for students with lower working memory capacities when confronted with complex subject matter.

The researchers compared retrieval practice directly with restudy among learners with high and low working memory capacities using low-complexity and high-complexity materials. When engaging with low-complexity material, students with low working memory capacity in the retrieval practice group significantly outperformed their peers in the restudy group. Conversely, when studying high-complexity material, this retrieval practice advantage emerged among learners with high working memory capacity.

Experiment 2 assessed targeted repeated retrieval practice schedules for fourth-grade students with low working memory capacity learning complex materials. Repeated retrieval practice under the schedules tested in Experiment 2 improved post-test performance compared to restudy for this cohort.

The researchers also examined diminishing-cues retrieval practice for learners with low working memory capacity working with complex materials. The results demonstrated that diminishing-cues retrieval practice produced superior post-test performance compared to restudy.

The findings indicate that learning-material complexity moderates the effectiveness of the testing effect across different levels of working memory capacity.

In the discussion of their findings, the authors emphasized that learning material complexity acts as a critical moderating factor in the relationship between working memory capacity and the testing effect. The investigators noted that standard retrieval practice alone did not produce uniform advantages across all student profiles and material types.

The study was authored by Xin Lu of Hengyang Normal University, together with Kejia Qu, Yuanlin Sun, and Ya Yang of the School of Psychology at Liaoning Normal University, with correspondence addressed to Lu and Qu. The research manuscript was submitted on 30 July 2026 and accepted for publication on 22 October 2026 by the journal Frontiers in Psychology, appearing in its Educational Psychology section. The authors distributed their article under an open-access Creative Commons Attribution license, noting that all claims and findings represent the evaluations of the contributing researchers.

Subject of Research: Working memory capacity and material complexity in retrieval practice

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

Article References: Lu, X., Qu, K., Sun, Y., & Yang, Y. (2026). The influence of working memory capacity and material complexity on the testing effect. Frontiers in Psychology, 17, Article 1952951. https://doi.org/10.3389/fpsyg.2026.1952951

Image Credits: AI Generated

DOI: 10.3389/fpsyg.2026.1952951

Keywords: testing effect, working memory capacity, material complexity, retrieval practice, educational psychology, primary school students, diminishing-cues retrieval practice, restudy, influence, working, memory, capacity