ABSTRACT
Thurstone (1938) believed that intelligence could only be defined in terms of a domain of essential mental abilities. He used empirical, experimental methods to identify the domain of skills that comprise intellectual behavior. Primary mental abilities represent these component skills of intelligence. Primary abilities may be combined to define larger intellectual components, such as those described by Cattell (see chapter 4), which in turn may be combined to define the concept of intelligence. Primary mental abilities are the cognitive skills that enable individuals to learn, think, and reason. These abilities are called on in the performance of real-world tasks. Differences in primary abilities account for differences in individual cognitive performances.
