The role of Thurstone's multidimensional model.
The model of the modern Binet represents an attempt to place an evaluation of g in the context of a multidi- mensional model of intelligence from which one can evaluate specific abili- ties. The impetus for a multidimensional model stemmed from the work of Thurstone (1938). He argued that, contrary to Spearman's notion of intelli- gence as a single process, intelligence could best be conceptualized as com prising independent factors, or "primary mental abilities." Years of painstak- ing work ultimately revealed evidence for group abilities factors that were relatively, but not totally, independent. The group factors were correlated, and from them a g factor could be extracted, as in the hierarchical model of the modern Binet.