Shared home environment has almost no effect on intelligence variance.

Evidence

By comparing these MZ-apart twins with monozygotic twins who had grown up together, Bouchard and his colleagues (1990) calculated that about 70% of the variance in intelligence was inherited. … Growing up in the same home seemed to have almost no effect. — Bob Altemeyer, The Authoritarian Specter, 887

Categorization

• XREF: Connects to the hereditarianism debate (The Nurture Assumption by Judith Rich Harris) and twin studies literature.
• QUESTION: This 70% heritability figure — how well has it withstood later large-scale GWAS findings and criticism of twin-study assumptions?