rman posited the existence of g when he found that results tests of varying, specific focus - measuring various abilities - were positively correlated in each individual. That is, how one performed on one task was positively correlated to how one performed on a separate, unrelated task. Thus, while s represents how one performs on a particular task, and varies across tasks, a general factor will emerge, g, which describes one's general ability to perform all tasks. In other words, Spearman thought he had discovered a quantifiable quotient of intelligence.
One proposal [regarding the nature of g] was that individual differences in g might be understood in terms of differences i
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