A reader sent me the following email:

“I’ve always wondered if a person with strong drawing (or painting) abilities would score well on perceptual reasoning. Is there a correlation? If so is it a very strong and clear correlation?”

I don’t think there is. A study of prodigies documents a case of a painting prodigy who scored IQ 88 (U.S. norms) in spatial ability (bottom fifth of Americans her age)

At the time of testing, prodigy seven, a self-taught painter, was nineteen years of age. Although she had been interested in arts and crafts for as long as she could remember, she did not begin to paint until she was 13 years old. She said she was inspired by a young art prodigy she saw on television. After just eighteen months of painting, the prodigy won the National Gold Key award, the most prestigious art award given to high school students, at the age of 15. She was one of 50 recipients of the award across the country. At nineteen, her work is selling for thousands of dollars and is displayed in prestigious art museums around the world.

Testing results

Total IQ Score= 112; Fluid reasoning= 100; Knowledge= 128; Quantitative Reasoning= 100; Visual Spatial Abilities= 88; Working Memory= 138

It seems artistic ability requires certain special abilities, like being able to differentiate hues that have little to do with the perceptual reasoning tasks on tests like the WAIS or the Binet.
Another reader sent me the following email:

“So I’ve stumbled across one of your articles in your blog, and in it you said that WAIS IV has correlation with g of 0.9 (if I’m not mistaken?). Also somewhere in the comments I’ve read that Raven’s Advanced Progressive Matrices has correlation with g of 0.8 (if I’m not mistaken?).

Where do these numbers come from?
Also if these are correct, does that mean that WAIS IV should give you a better representation of your ‘overall’ intelligence?
So to clarify, does higher g-loading mean that the test is better approximation for your ‘true’ IQ?