ABSTRACT
Despite such problems, some general facts and conclusions cannot be overlooked. One pervasive fact is that when a range of intellectual problems (tests) varying in content and format is administered to a sample of individuals, a
matrix of positive test score correlations is obtained. The pattern of data supports a hierarchical model with a general ability, g, underlying all cognitive performance as well as several specific abilities. Theorists have attempted to simplify the interpretation of correlations by way of general and specific abilities organized in a hierarchical or multidimensional scheme. One way to view factor theories is in terms of a structural model of human intellect. Unfortunately, factor theories do not provide a satisfactory way of defining exactly what a factor or ability might be. A factor is a hypothetical entity, an abstraction, that an individual possesses to varying degrees. But what is it that an individual actually possesses when he or she has high levels of g or, more importantly, scores well on tests of some specific ability. In short, a factor is a mathematical abstraction that is interpreted after the fact by the theorist. The interpretation is based on an intuitive analysis of the content of tests that load on the same factor and the apparent intellectual demands for solving the individual problems.
