Plastic and immobile: Unequal intergenerational mobility by genetic sensitivity score within sibling pairs

Area of Science:

• Behavioral genetics
• Sociology
• Developmental psychology

Background:

• Traditional biological arguments often posit genotype as a mediator of parent-child economic similarity.
• The differential susceptibility model proposes that genotype may moderate, rather than mediate, such similarities.
• Understanding genetic influences on socioeconomic status is crucial for addressing intergenerational inequality.

Purpose of the Study:

• To investigate the relationship between sensitive genotypes and intergenerational economic mobility.
• To test the differential susceptibility model's predictions regarding genetic influences on economic outcomes.
• To differentiate between mediation and moderation effects of genotype on parent-child economic similarity.

Main Methods:

• Utilized family fixed effects models with sibling data from the Add Health study.
• Employed an index of sensitive genotypes as the primary genetic measure.
• Conducted full, same-sex sibling comparisons to control for parental characteristics and non-random genotype distribution.

Main Results:

• Individuals with more copies of sensitive genotypes exhibited lower economic outcomes in low-income contexts compared to their siblings.
• Conversely, those with sensitive genotypes fared better in high-income contexts than their siblings.
• This genetic sensitivity to parental income was associated with reduced intergenerational economic mobility.

Conclusions:

• Results support the differential susceptibility model, indicating genotype moderates environmental influences on economic outcomes.
• Findings contradict simplistic genetic explanations for intergenerational inequality.
• Sensitive genotypes are not inherently advantageous or disadvantageous but amplify the impact of parental socioeconomic context, increasing dependence and reducing mobility.