Capacity, Control, or Both – Which Aspects of Working Memory Contribute to Children’s General Fluid Intelligence?

Starting from the assumption that working memory capacity is an important predictor of general fluid intelligence, we asked which aspects of working memory account for this relationship. Two theoretical stances are discussed. The first one posits that the important explanatory factor is storage capacity, roughly defined as the number of chunks possible to hold in the focus of attention. The second one claims that intelligence is explained by the efficiency of executive control, for instance, by prepotent response inhibition. We investigated 96 children at the age between 10 and 13. They completed a version of the n-back task that allows assessment of both storage capacity and inhibitory control. They also completed Raven’s Progressive Matrices as the fluid intelligence test and the Test for Creative Thinking - Drawing Production, for control purposes. We found that Raven’s scores correlated negatively with the number of unnecessary responses to irrelevant stimuli but they did not correlate with the number of signal detections. We conclude that children’s fluid intelligence depends on inhibitory control, with no relationship with storage capacity.