Plenty is doing.
"The degree to which various psychometric tests, such as the Wechsler subscales, are correlated with certain non-psychometric variables is found to be directly related to the tests' g loadings. This relationship has been found for: the heritability of various tests; the spouse correlations and other kinship correlations on various tests; the degree of inbreeding depression of scores on various tests, and its converse, hybrid vigor (variables which, in genetic theory, have important implications concerning the evolution of g); evoked potentials of the brain; the size of the average black-white difference; and reaction time (averaging less than one second) on very simple tasks that require no knowledge or acquired specific skills. Therefore, g is no mere artefact of psychometrics or factor analysis, as some psychologists have mistakenly believed, but it is a real phenomenon, a variable which links psychology to biology and evolution."
Disclaimer: this quote appears here only to spark discussion. It is not endorsed one way or the other. Make up your own mind. Or just refresh the page for another viewpoint. From a collection assembled by the late Chris Brand.