Editing Race and intelligence (section)

===Socioeconomic environment===
Different aspects of the socioeconomic environment in which children are raised have been shown to correlate with part of the IQ gap, but they do not account for the entire gap.{{sfn|Hunt|2010|page=428}} According to a 2006 review, these factors account for slightly less than half of one standard deviation.<ref>{{cite journal |last1=Magnuson |first1=Katherine A. |last2=Duncan |first2=Greg J. |title=The role of family socioeconomic resources in the black–white test score gap among young children |journal=[[Developmental Review]] |date=December 2006 |volume=26 |issue=4 |pages=365–399 |doi=10.1016/j.dr.2006.06.004}}</ref>

Other research has focused on different causes of variation within low socioeconomic status (SES) and high SES groups.<ref name="Scarr-Salapatek1971">{{cite journal |last1=Scarr-Salapatek |first1=S. |year=1971 |title=Race, social class, and IQ. |journal=Science |volume=174 |issue=4016 |pages=1285–95 |doi=10.1126/science.174.4016.1285 |pmid=5167501 |bibcode=1971Sci...174.1285S}}</ref><ref name="Scarr-Salapatek1974">{{cite journal |last1=Scarr-Salapatek |first1=S. |year=1974 |title=Some myths about heritability and IQ. |doi=10.1038/251463b0 |journal=Nature |volume=251 |issue=5475 |pages=463–464 |bibcode=1974Natur.251..463S |s2cid=32437709 |doi-access=free}}</ref><ref name="Rowe1994">D. C. Rowe. (1994). ''The Limits of Family Influence: Genes, Experience and Behaviour''. Guilford Press. London</ref>
In the US, among low SES groups, genetic differences account for a smaller proportion of the variance in IQ than among high SES populations.<ref name="Kirkpatrick2015">{{cite journal |last1=Kirkpatrick |first1=R. M. |last2=McGue |first2=M. |last3=Iacono |first3=W. G. |year=2015 |title=Replication of a gene-environment interaction Via Multimodel inference: additive-genetic variance in adolescents' general cognitive ability increases with family-of-origin socioeconomic status |doi=10.1007/s10519-014-9698-y |journal=Behav Genet |volume=45 |issue=2 |pages=200–14 |pmc=4374354 |pmid=25539975}}</ref> Such effects are predicted by the ''[[Bioecological model|bioecological]]'' hypothesis—that genotypes are transformed into phenotypes through nonadditive synergistic effects of the environment.<ref>{{Cite journal |title=Nature-nuture reconceptualized in developmental perspective: A bioecological model. |journal=Psychological Review |pages=568–586 |volume=101 |issue=4 |doi=10.1037/0033-295x.101.4.568 |first1=Urie |last1=Bronfenbrenner |first2=Stephen J. |last2=Ceci |pmid=7984707 |date=October 1994|s2cid=17402964 }}</ref> {{harvp|Nisbett|Aronson|Blair|Dickens|2012a}} suggest that high SES individuals are more likely to be able to develop their full biological potential, whereas low SES individuals are likely to be hindered in their development by adverse environmental conditions. The same review also points out that adoption studies generally are biased towards including only high and high middle SES adoptive families, meaning that they will tend to overestimate average genetic effects. They also note that studies of adoption from lower-class homes to middle-class homes have shown that such children experience a 12 to 18 point gain in IQ relative to children who remain in low SES homes.{{sfn|Nisbett|Aronson|Blair|Dickens|2012a}} A 2015 study found that environmental factors (namely, family income, maternal education, maternal verbal ability/knowledge, learning materials in the home, parenting factors, child birth order, and child birth weight) accounted for the black–white gap in cognitive ability test scores.{{sfn|Cottrell|Newman|Roisman|2015}}