Numerous studies have suggested a relationship between working memory and mathematical ability. However, despite theclear relationship between these two constructs, it is still unclear why working memory might be related to mathematicalability. In the current study, we tested three possible theories, the Positive Manifold, a mediation model, and a Transac-tional model. Using path analyses in a structural equation modeling (SEM) framework, fit indices indicated an excellent fitfor the Transactional model, while a poor fit was shown for the remaining models. This finding may suggest that workingmemory and mathematical ability interact in a recursive manner over time, and essentially influence one another over adevelopmental trajectory. Findings may demonstrate the continued importance of working memory early in developmentand understanding how improving working memory may help struggling students in mathematics.

Sketching is often a helpful strategy for solving science problems. We examined the role of visuo-spatial working memoryand sketching in predicting science problem solving accuracy. Sketches were coded for quality based on whether theyincluded elements and relationships in the sketches. Regression analyses were done regressing working memory onto science problem solving. A mediation analysis was also conducted to determine whether sketch quality mediated therelationship between working memory and science accuracy. Findings are discussed in terms off implications for educationand classroom instruction.