This long awaited work surveys and summarizes the results of more than seventy years of
investigation, by factor analysis, of a variety of cognitive abilities, with particular attention to
language, thinking, memory, visual and auditory perception, creativity and the production of
ideas, and the speed and accuracy of mental processing. The author describes his detailed
findings resulting from reanalysis of more than 460 data sets from the factor-analytic
literature, followed by a presentation of a hierarchical, three-stratum theory of cognitive …