Modern factor analysis is the outgrowth of Spearman's original "2-factor" model of intelligence, according to which a mental test score is regarded as the sum of a general factor and a specific factor. As early as 1914, Godfrey Thomson realized that the data did not require this interpretation and he demonstrated this by proposing what became…

The factor-analytic history of the isolation and identification of the cognitive ability construct known as Number or Numerical Facility is described. Empirical documentation from the psychometric literature is discussed, and examples of items from a variety of tests which have defined and been associated with the Number factor are included to…

The complex and multi-faceted nature of the cognitive process of reasoning is discussed. The factor-analytic history of the isolation and definition of the three most important currently recognized reasoning factors (general reasoning, induction, and logical or deductive reasoning) is traced through the psychometric literature, and the…

The Stanford-Binet Intelligence Scale: Fourth Edition is a conceptually new version of this traditional intelligence scale. The new scale has a solid basis in theory, but there is little evidence that the Binet matches its intended theory. This study was designed to determine whether the Binet corresponds to the theory that guided its…

The complex nature of the psychological construct called judgment, the history of its identification as a mental ability, its measurement, and its relationship to other mental abilities are discussed. Factor analytic research which isolated the judgment factor is reviewed. The pervasiveness of the judgment factor throughout a number of diverse…