Subtest Heritability

Seems queer to argue brain differences are purely due to environment when other areas of the body are not controversial to say differ due to genes across groups
http://www.cell.com/current-biology/abstract/S0960-9822(15)00671-5
https://bmcevolbiol.biomedcentral.com/articles/10.1186/1471-2148-11-16
If anything, the brain differs more than other parts of the body, including pigmentation. And cultural/societal differences further compounded this, making us evolve rather quickly in a period of time due to differential fertility. Some societies, being smart was the best way to have the most surviving kids. Others, not so much
https://www.ncbi.nlm.nih.gov/pubmed/18087044
https://www.ncbi.nlm.nih.gov/pubmed/25748943
https://en.wikipedia.org/wiki/The_10,000_Year_Explosion

https://en.wikipedia.org/wiki/G_factor_(psychometrics)#cite_ref-RJ2010_31-1

https://www1.udel.edu/educ/gottfredson/30years/Rushton-Jensen30years.pdf

https://medium.com/@houstoneuler/the-cherry-picked-science-in-voxs-charles-murray-article-bd534a9c4476

http://laplab.ucsd.edu/articles2/Lee2010.pdf

John Baker, Race (London: Oxford University Press, 1974), pp. 360-400.

"The Persisting Racial Chasm in Scores on the SAT College Entrance Examination," Journal of Blacks in Higher Education, Autumn, 2009, p. 85.

Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans, Science, September 9, 2005: Vol. 309 no. 5741 pp. 1717-1720, Patrick D. Evans, Bruce T. Lahn, et. al.

Antonio Regalado, Head Examined: Scientist's Study of Brain Genes Sparks a Backlash, Wall Street Journal, June 16, 2006.

Rushton, J. P. & Ankney, C. D. (1996). Brain Size and Cognitive Ability: Correlations with Age, Sex, Social Class, and Race. Psychonomic Bulletin & Review, 3, 21-26.

Gottfredson, L. S. (2006). Social consequences of group differences in cognitive ability (Consequencias sociais das diferencas de grupo em habilidade cognitiva). In C. E. Flores-Mendoza & R. Colom (Eds.), Introducau a psicologia das diferencas individuais (pp. 433-456). Porto Allegre, Brazil: ArtMed Publishers.

Wolff, Henry. "Eye Size, Brain Size, and Intelligence." American Renaissance 22.9 (2011): n. pag. Web. http://www.amren.com/ar/2011/09/index....

Cochran, Gregory, and Henry Harpending. The 10,000 Year Explosion: How Civilization Accelerated Human Evolution. New York: Basic, 2009. Print.