More indications that g is a myth

One indication that Spearman's g (upon which IQ is based) is an artifact of positive correlations among various intelligence test measures than a real thing is that there are subpopulations among which these measures do not correlate in the same way as among the general public.

An example is here: (note, my interpretation of their findings):

Psychol Sci. Author manuscript; available in PMC 2015 Jan 8.

Published in final edited form as:

Psychol Sci. 2007 Aug; 18(8): 657–662.

doi:  10.1111/j.1467-9280.2007.01954.x

PMCID: PMC4287210

NIHMSID: NIHMS653064

The Level and Nature of Autistic Intelligence

Michelle Dawson,¹ Isabelle Soulières,^1,2 Morton Ann Gernsbacher,³ and Laurent Mottron^1,2

To quote:

For example, no autistic child scored in the “high intelligence” range on the WISC-III, whereas a third of the autistic children scored at or above the 90th percentile on the Raven’s Matrices. Only a minority of the autistic children scored in the “average intelligence” range or higher on the WISC-III, whereas the majority scored at or above the 50th percentile on the Raven’s Matrices. Whereas a third of the autistic children would be called “low functioning” (i.e., in the range of mental retardation) according to the WISC-III, only 5% would be so judged according to the Raven’s Matrices.

In striking contrast to the autistic children, the nonautistic control children did not show a significant difference between their Raven’s Matrices scores and their WISC-III Full Scale, Verbal Scale, or Performance Scale scores .

So, if there was a real thing X corresponding to Spearman's g that represented the intelligence of a human brain, then the general positive correlation in the general population between WISC and Raven's Matrices is not measuring this thing X.  But it is these kinds of positive correlations among the various tests' results that is supposed to be measuring this real thing that is approximated by Spearman's g.