Abstract
More intelligent individuals typically show a higher speed of information processing. However, individual differences in reaction times do not represent individual differences in a single, but in multiple cognitive processes. Therefore, it is unclear whether the association between mental speed and intelligence reflects advantages in a specific cognitive process or in general processing speed. I will present a neurocognitive psychometrics account of mental speed that decomposes the relationship between mental speed and intelligence using mathematical models of cognition and chronometric analyses of neural processing to identify distinct stages of information-processing strongly related to intelligence differences. Evidence from both approaches suggests that smarter individuals show a greater speed of higher-order processing, which may reflect advantages in the structural and functional organization of brain networks and which facilitates the transmission of information from frontal attention and working memory processes to temporal-parietal processes of memory storage.