A twin study of intelligence in Russia.
Twin data from prewar Russia show the same effect of family environment on intelligence as in contemporary America.
D000293:Adolescent; D002648:Child; D003431:Cross-Cultural Comparison; D004777:Environment; D005260:Female; D005824:Genetics, Behavioral; D005838:Genotype; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D011247:Pregnancy; D012737:Sex Factors; D014427:Twins; D014586:USSR; D014481:United States