Because cold adapted populations tend to score higher than tropical populations on IQ tests, it can be inferred that human intellect reached its pinnacle after we left the tropics. But correlation does not equal causation. Some folks think that because civilization began outside the tropics, that explains why the tropics fell behind and that somehow before civilization, cold adapted peoples were no smarter than warm adapted people. After all, IQ was useless in the stone age right?
Arthur Jensen notes that “On non-verbal reasoning tests given in the first grade, before schooling could have much impact,” Native American “children exceeded the mean score of blacks by the equivalent of 14 IQ points.” Jensen claimed they also score higher on achievement tests from first to twelfth grade, and this DESPITE Native Americans ranking as far below Blacks in socio-economic status as Blacks rank below Whites.
Did you hear that? DID YOU HEAR THAT AMERICA? As Oprah would say.
When I read that today I thought Jensen must be mistaken. Hate to say it but the majority of Native Americans I’ve met were homeless, drunk, barely coherent and missing teeth. I can’t imagine a more environmentally deprived community in a First World country and yet these people outscore black Americans by 14 points on performance IQ (at least in early childhood).
I decided to look for more recent research since Jensen’s book was from 1981. I found a 1996 paper in which 28 American Indian school-aged children ranging in age from 6 years
to 17 years (from a random sample of 30 selected from students participating in a community program through the Division of Indian Work in Minneapolis, Minnesota) were given the WISC-III. Their verbal, performance and full-scale IQs were 90.5, 102.3, and 97.4 (U.S. norms) respectively.
To put that in perspective, in the WISC-III standardization, the corresponding scores were 103.6, 102.9, and 103.5 for Whites and 90.8, 88.5, and 88.6 for Blacks.
It should be noted that the American Indians were tested in 1994 and the WISC-III standardization occurred in 1989 so at most we could reduce the American Indians to 90, 100.3 and 95.9. Also, the Native Americans were a bit atypical in that they were from an urban as opposed to reservation environment, but this should make the comparison more fair.
If we assume that on a scale where Americans have an SD of 15, White Americans have an SD of 14.5, then on a scale where the White American mean and SD is set at 100 and 15 respectively, Native Americans scored 86, 97 and 92 and Black Americans scored 87, 85 and 85.
It should also be noted that Black Americans average about 25% white genetically so their scores might be reduced to 83, 80 and 80 if unmixed.
The 17 point gap in Performance IQ between Native Americans and unmixed Blacks can not at all be explained by environment so it must be genetic but it can’t at all be explained by selection pressures related to civilization, since most Native Americans didn’t have any. Maybe it’s genetic drift, but most likely it’s selection pressures related to cold winters and that explains why the Performance IQ gap is quadruple the verbal one. Cold winters require require visuo-spatial motor abilities to sew, hunt, make tools, make shelter, build fire, make clothes etc. This also explains why men tend to outperform women especially on spatial tasks (men did the hunting, women did the child rearing).