A process-based account of the speed-ability relationship for the Posner Task

A process-based approach is selected for studying the relationship between intelligence and the speed of information processing on the basis of the Posner Task. By applying meta-analytic methods, several studies involving this letter-matching task were used for gaining a large data set. Within the Posner Task, participants had to react to stimuli according to two different instructions. The first instruction required mainly perceptual processes, whereas the second involved mostly memory processes. Using a model with fixed links between manifest and latent variables, and a step-wise procedure to determine parameters, enabled us to study the influences these processes have on intelligence individually. The results of our study show a much stronger influence of memory processes than of perceptual processes. Also our study illustrates the advantages a fixed-links model can have in studying separate influences of processes, as opposed to a standard structural equation model.