Relations among mental capacity, Short-term Storage Space, and operational efficiency

According to R. Case, a subject's Total Processing Space is the sum of his Short-term Storage Space (STSS) and Operating Space (OS). Case has hypothesized a trade-off between the two, that is, an increase in operational efficiency leads to a decrease in operating space, and consequently more short-term space is available for information processing. To test Case's hypothesis 52 freshman students were tested to estimate operational efficiency (time taken to finish the Figural Intersection Test, when administered with a time limit), Pascual-Leone's Structural M-capacity, Ms (i.e., STSS), and Functional M-capacity, Mf. A zero correlation was obtained between operational efficiency and Ms/STSS, which suggests that subjects find it difficult to distribute attentional load from one reserve (OS) to another (STSS). This study supports Pascual-Leone's construct of Ms and Mf. It is concluded that subjects with high operational efficiency seem to be operating with the field-independent cognitive style rather than using a strategy of decreasing operating space.