The
g factor (also known as
general intelligence,
general mental ability or
general intelligence factor) is a construct developed in
psychometric investigations of
cognitive abilities and human
intelligence. It is a variable that summarizes positive
correlations among different cognitive tasks, reflecting the fact that an individual's performance on one type of cognitive task tends to be comparable to that person's performance on other kinds of cognitive tasks. The
g factor typically accounts for 40 to 50 percent of the between-individual performance differences on a given
cognitive test, and composite scores ("IQ scores") based on many tests are frequently regarded as estimates of individuals' standing on the
g factor. The terms general intelligence, general cognitive ability, general mental ability, or simply intelligence are often used interchangeably to refer to this common core shared by cognitive tests.