Shadoom

http://humanvarieties.org/2013/05/26/the-onset-and-development-of-b-w-ability-differences-early-infancy-to-age-3-part-1/

Infants, as they age, international hierarchies, mixed pops

http://www.oecd.org/pisa/

http://akarlin.com/2012/08/minorities-cognitive-performance-in-the-uk/

https://twitter.com/thealthype/status/806295599712768001

Lynn 2006