Uncovering the reciprocal relationship between domain-specific and domain-general skills: Combined numerical and working memory training improves children's mathematical knowledge

The acquisition of domain-specific number knowledge and domain-general cognitive processes, including working memory, have shown to contribute to math learning and achievement. Correlational work has emphasized a reciprocal relationship between these processes; however, little is known about their relative and causal contributions to math learning. Here, we test the individual and additive benefits of playing tablet-based games targeting domain-specific and domain-general skills to improve mathematical knowledge and working memory in a diverse population of kindergarten children (N = 235, 50 % female, 45 % Hispanic/Latino, 35 % African American/Black, 21 % White, 6 % biracial/mixed race, 51 % annual household income less than $30,000). Our results provide causal evidence for the reciprocal relations between numerical knowledge and working memory. Specifically, we found that playing a working memory game led to improvements in mathematical knowledge as compared to an active control and after taking into account baseline performance. Importantly, we also found that children who played both a working memory game and a numerical knowledge game showed the most pronounced and sustained benefits in mathematical knowledge, with benefits remaining present several weeks after intervention completion. Our findings illustrate the importance of targeting both domain-general and domain-specific skills in order to maximize the benefits of interventions to improve mathematical knowledge. Yet, given the inconsistent results across various studies, we argue that it is critical to further investigate underlying mechanisms and training features, as even subtle variations seem to dramatically affect training outcomes.