What does the g factor refer to in intelligence testing?

The g factor, or general intelligence factor, is a concept introduced by psychologist Charles Spearman in the early 20th century. It refers to a core cognitive ability that underlies performance across a variety of mental tasks. Spearman proposed that individuals possess a certain overall cognitive capacity that influences their skills in specific areas, such as verbal reasoning, mathematical ability, and problem-solving.

The g factor is considered a measurable construct through standardized intelligence tests, which often yield a single score that represents an individual’s overall cognitive capability. This score is thought to reflect the individual's ability to process information and learn across different domains, indicating their potential for academic and intellectual performance.

In contrast to the general intelligence factor, specific skills and intelligences—like social or practical intelligence—refer to more narrowed abilities that do not necessarily correlate with g. Social intelligence, for instance, relates to an individual's capacity to navigate social interactions effectively, while practical intelligence pertains to the application of skills and knowledge in real-world settings. These concepts, while important in understanding the broader scope of intelligence, do not encapsulate the overarching cognitive capabilities that the g factor does.