General intelligence factor

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The General intelligence factor, often shortened to g, is a construct from psychology. The idea is that there is a common factor in intelligence tests. Simply speaking, this can then be called intelligence.

An illustration of Spearman's two-factor intelligence theory. Each small oval is a hypothetical mental test. The blue areas show the variance attributed to s, and the purple areas the variance attributed to g.

Charles Spearman, an early psychometrician, found that school children's grades across unrelated subjects were strongly related to each other. That is to say, children who were good at one area (such as reading) were also good in another area (such as math). He then proposed that these relationships reflected the influence of a dominant factor, which he called g for "general" intelligence. He developed a model where all variation in intelligence test scores can be explained by two factors. The first is the factor specific to an individual mental task: the individual abilities that would make a person more skilled at one cognitive task than another. The second is g, a general factor that governs performance on all cognitive tasks.

The accumulation of cognitive testing data and improvements in analytical techniques have preserved gs central role and led to the modern conception of g.[1] A hierarchy of factors with g at its apex and group factors at successively lower levels, is espoused to be the most widely accepted model of cognitive ability.[2] Other models have also been proposed, and significant controversy attends g and its alternatives.

References[change | change source]

  • Carroll, J.B. (1993). Human Cognitive Abilities. Cambridge University Press.