Commenter antjuanfinch runs a web site where one can take IQ tests that are fun and well programmed (though the norms may need revising). In the real World, antjuanfinch is a twenty-something African American who despite growing up in poverty with mentally ill parents, ended up at the most prestigious university on the planet: Harvard.

Recently, antjuanfinch was mysertiously offered a chance to take the WAIS-IV (4th edition of the Wechsler adult intelligence scale) for free and in the age of covid, this was taken on-line. atjuanfinch self-reported his scaled scores on each of the subtests which I posted below, along with index scores and full-scale IQ I calculated from the manual (which in some cases differed slightly from what atjuanfinch reported).

It should be noted that the scaled scores are expressed on a scale where the U.S. mean for each age group is 10 (SD 3) and the index scores/full-scale IQ use a scale where the U.S. mean for each age group is 100 (SD 15). Thus to convert the scaled scores to IQ equivalents, simply multiply by 5 and add 50. In the third column, scores are adjusted for the fact that the WAIS-IV norms were 16-years-old at the time of testing and these norms (at least in the short-term) tend to become inflated by the equivalent of a few IQ points a decade though this might be an over-correction since the Flynn effect may have stagnated or even reversed in recent years. We’ll have a better idea when the WAIS-V is released.

The results show that atjuanfinch is a man of very superior intelligence. His full-scale IQ of 130 exceeds that of 98% of Americans his age and is even above of the average of his fellow students at the World’s most prestigious university.

Comparison with Billy

It is interesting to compare his WAIS-IV scores to those of Billy, another brilliant black commenter on this blog. To better illustrate the comparison, I used the five index scores of the WISC-V (most recent Wechsler for children) rather than the four-factor model used by the most recent adult Wechsler.

Table 2
Billy antjuanfinch
verbal crystallized  145+  134
spatial  118  118
non-verbal conceptual  140  128
working memory  125  119
processing speed  111  114

It is interesting how both of these men have the same profile: verbal crystallized > non-verbal conceptual > working memory > spatial > processing speed.  Coincidence?  Both these men are brilliant blacks and brilliant folks by definition are high in g (general intelligence factor) and thus tend to do best on the most g loaded indexes. Verbal and conceptual tests tend to be the most g loaded, while processing speed is the least g loaded so smart people tend to be unexceptional there.  Processing speed is also a problem for those who are neuro-atypical which is common among this blog’s commenters though there’s no evidence these two commenters are in that camp.

In addition, blacks tend to do better on verbal as opposed to spatial tests,  perhaps because their ancestors never left the tropics so there was less natural selection for the spatially demanding skills needed to survive ice age winters (building shelter, sewing tight figure hugging clothes, making fire, hunting mammoths).  A similar cognitive difference evolved between the sexes, with men doing hunting and today scoring better on spatial tests.

antjuanfinch’s mother

It’s interesting that atjuanfinch reports his mother’s IQ as being 102.  Given the 0.45 parent-offspring IQ correlation,  and the fact that the average African American has a WAIS-IV IQ of 87.7,  we’d expect atjuanfinch’s mother to have an IQ of:

[atjuanfinch’s IQ – (U.S. black mean)](parent-off spring correlation) + black mean [130 – 87.7](0.45) + 87.7

42.3(0.45) + 87.7

107 (only 5 points from the score atjuanfinch reported).