Outrageous fortune or destiny? The impacts of both the genes and the family environment tended to decline over the life course, resulting in a downward trend in family influences from all sources

Outrageous fortune or destiny? Family influences on status achievement in the early life course. J. Micah Roosa, François Nielsen. Social Science Research, https://doi.org/10.1016/j.ssresearch.2018.12.007

Abstract: Psychologists using quantitative studies of the trait intelligence have established with much confidence that the impact of genes on intelligence increases with age, while the environmental effect of the family of origin declines. We examined the conjecture that a similar trend of increasing effect of genes/declining family environmental effect characterizes other status-related outcomes when arranged in typical age-graded sequence over adolescence and early adulthood. We used DeFries-Fulker (1985) (DF) analysis with longitudinal data on 1576 pairs of variously-related young adult siblings (MZ twins; DZ twins; full siblings; half siblings; cousins; and nonrelated siblings; mean age 28) to estimate univariate quantitative genetic decompositions for fifteen status-related outcomes roughly ordered along the early life course: Verbal IQ, High school GPA, College plans, High school graduation, Some college, College graduation, Graduate school, Educational attainment, Occupational education, Occupational wages, Personal earnings, Household income, Household assets, Home ownership, and Subjective social status, with and without covariate controls for Age, Female gender, and Race/ethnicity (black, Hispanic, other; reference white). Results for successive outcomes did not support the conjecture of increasing heritability with maturity. Rather, the impacts of both the genes and the family environment tended to decline over the life course, resulting in a downward trend in family influences from all sources. There was some evidence of a recrudescence in relative influence of the family environment for outcomes related to the household that are often shared with a spouse, such as home ownership, suggesting a role of assortative mating in status reproduction. Other findings and limitations of the study are discussed.

Check also Talent vs Luck: the role of randomness in success and failure. A. Pluchino. A. E. Biondo, A. Rapisarda. arXiv:1802.07068 [physics.soc-ph], Feb 20 2018, https://www.bipartisanalliance.com/2018/02/if-it-is-true-that-some-degree-of.html