Despite the existence of numerous studies that examined the relationship between working memory capacity and performance in complex cognitive tasks, it remains unclear whether this capacity is domain specific or domain general. In addition, the available empirical evidence is somewhat contradictory. In this work we have studied the role of verbal working memory capacity in a non-verbal task – mental image rotation. If this capacity were domain specific it would be expected that high and low verbal span participants would obtain similar results in the mental rotation task. We have found that this is not the case as the high span participants performed better in terms of both speed and accuracy. Moreover, these differences depended on the processing component of the mental rotation task: the higher the processing requirements the higher the differences as a function of the working memory capacity. Therefore, the evidence presented here supports the domain general hypothesis.

This study identified the cognitive processes that underlie the individual differences in early mathematical performance in elementary school children. Taking into account the Baddeley framework multicomponent model, the inhibitory processes, working memory, phonological awareness, and naming speed are considered to be related to early math learning. To examine this relationship, we compared the performance of a total of 424 typically developing middle-class children, aged between 4 and 7 years in a battery of cognitive and early numeric tests: The Utrecht Early Numeracy Test, the Rapid Automatized Naming Test, Spanish version of the Stroop task, the Numeracy Interference Test, Digit Span test, and Phonological Knowledge Test. The mean age of the participants was 72.21 months (sd = 14.8), and 48.6% were male and 51.4% were female. The results demonstrated that children performing worst on central executive, phonological processing, and inhibitory processes showed lower results in early mathematical tasks measured by The Utrecht Early Numeracy Test. Results supported the notion that the executive system is an important predictor of children's mathematical performance.