Y’all remember this test from back in April 2017?
It turns out it might have been more accurate than I thought. On page 221-222 of Bias in Mental Testing, Jensen describes the most comprehensive factor analysis ever done.
Hakstian and Cattell (1974) administered 57 ability tests to 343 adults averaging 23.7 years of age. The tests are extremely diverse and probably constitute the most complete samplings of the domain of cognitive tests to be found in the entire literature. Each of the fifty-seven tests was homogeneous in content so as to be highly representative of a particular primary mental ability. It would be hard to imagine a much greater variety of tests than the fifty-seven tests included in this battery. Hakstian and Cattell factor analyzed the battery, which yielded nineteen significant interpretable primary factors that were rotated to oblique simple structures , that is, the primary factors were intercorrelated. Each of the primary factors is represented by three similar tests.
I have factor analyzed the matrix of intercorrelations among the nineteen primary factors. The results are shown in table 6.14. (The factors resulting from a factor analysis of oblique primary factors are called second-order factors.)

Now for the really interesting part:
The highest g loadings are found on speed of closure (0.77) and inductive reasoning (0.72). Speed of closure involves the ability to complete a gestalt when parts of the stimulus are missing. Time needed for recognition of mutilated words is a measure of this ability. It involves a kind of perceptual inference, of mentally filling in the gaps or “seeing” the relationships among the parts to form a recognizable or familiar whole.
So there you have it: the most g loaded type of test ever discovered are Gestalt.
Not only is the Gestalt test incredibly g loaded, but it’s very culture reduced.
Ironically it was commenter Mug of Pee who selected the items on the Gestalt test I used to test people here and yet the same Mug of Pee states: ” you have to give up on g or give up on the idea of culture reduced tests.”
While it’s true that culture reduced tests are often less g loaded than culture loaded tests, Gestalt is a massive exception. It’s this test that should be used for cross-cultural research, not the Raven Progressive Matrices.