Cro-Magnon man dominated Europe from about 45,000 years ago to 10,000 years ago.  Although they are sometimes considered the first Whites, the white gene pool is more complex given the spread of agriculture from the Middle east and actual white skin is thought not to have appeared until 7000 years ago, so Cro-Magnon’s probably looked liked this.

Brain Size suggests an IQ of 92 to 99

Commenter Milo wanted me to estimate their IQ from their brain size and using my line of best fit, which predicts mean genetic IQ (y) from mean genetic brain size (x) in 13 modern races, I can possibly do so.

About 15,000 years ago their cranial capacity was 1450 cc, suggesting an IQ of 92, but by 10,000 years ago, the incredible cognitive demands of surviving ice age Europe had raised their brain sizes to 1518 cc, suggesting an IQ of 99.

Draw-A-Man IQ test suggests an IQ of 75

To validate these IQ estimates, I decided to look at their cave art, with an emphasis on drawings of people, so I could apply Dale Harris’s revision of the beloved Goodenough Draw-A-Man IQ test.  The first drawing of a man I found was discovered in South-western France and believed to be 17,000 years old.  It’s known as “The Wounded Man”.

The Goodenough Harris Draw-A-Man test has a maximum raw score of 73, but because this drawing depicted the man with the head of a bird, not a human, 13 of the items dealing with features unique to the human head could not be scored, so it ended up with a score of 22/60 which I then prorated to 27/73.

Another mysterious cave painting found in the cavern known as ‘The Sanctuary’ at Trois-Frères, Ariège, France, made around 15,000 years ago is known as “The Sorcerer”.

Unfortunately this too is a man-animal hybrid, and the animal features made some of the items inapplicable, in this case, the six items dealing with clothing (items #29,#55,#56,#57,#58 and #59), but out of the remaining 67 items, the picture scored 49, which I prorated into a score of 53/73.

Averaging the two drawings together, Cro-Magnon man scored 40/73 on the Goodenough-Harris Draw-A-Man test.  The smoothed mean and standard deviation for U.S. 15-year-olds (considered adult level for the purpose of this test) is 45.2 and 9.83  respectively, so this equates to an IQ of 92 (U.S. norms) or 90 (U.S. white norms).  But because these norms were published in 1963, and norms on this test became inflated at a rate of 3 IQ points per decade (Lynn, 2006) until at least 2006, we must reduce this IQ to 77 on modern white norms.

Correcting for culture bias, Draw-A-Man test suggests an IQ of 95

Because even the Draw-a-man test is culturally biased, we must do our best to adjust for the stone age environment Cro-Magnons lived in.  It’s well known that on typical IQ tests, dropping out of school causes IQ scores (though perhaps not real intelligence) to drop by 2 points per missed year, and research on adopted kids shows that each extra year of education in the rearing parent raises a child’s IQ score by 1.17 points.  Although such cultural biases fade by adulthood, as scholars Dickens and Flynn brilliantly noted, this is only true within generations.  Between generations these environmental effects are permanent.

So considering the average Cro-Magnon had about 13 years less schooling than today’s average white, this would artificially depress his IQ by 26 points.  Further, being raised by parents with 12 less years schooling than today’s average white would artificially depress his IQ by 14 points. So these two cultural biases together should artificially depress his IQ by 40 points on a typical IQ test, but because the Draw-A-Man test is only about half as culturally biased as a typical IQ test, we’ll say it’s depressed by only 20 points.

You might ask, why, if the Draw-A-Man test is only half as culturally biased as a typical IQ test, does it show the full 3 point a decade Flynn effect.  The answer is because the Flynn effect is not entirely cultural, it’s also biological (nutrition) and Performance IQ tests like Draw-a-man are sensitive to nutrition (which Cro-Mangnons had plenty of).

So adding 20 IQ points to their IQ of 77, to compensate for the test’s cultural bias, raises them to IQ 97.

I realize such corrections are very simplistic, but it seems to give believable results.