Differential application of cultural practices at the family and individual levels may alter heritability estimates.

Uchiyama et al. emphasize that culture evolves directionally and differentially as a function of selective pressures in different populations. Extending these principles to the level of families, lineages, and individuals exposes additional challenges to estimating heritability. Cultural traits expressed as a function of the genetics whose influence they mask or unmask render inseparable the influences of culture and genetics.