The current project is the first comprehensive quantitative review of genetic and environmental mechanisms of differential stability of personality across the lifespan. Replicating previous findings (Ferguson, 2010; Roberts & DelVecchio, 2000), trait stability increased monotonically until age 30 with a possible stall in early childhood. We, however, found no clear evidence for continued increases in phenotypic stability, a pattern that is consistent with some previous research (Ferguson, 2010; Terracciano et al., 2006) and inconsistent with others (Lucas & Donnellan, 2011; Roberts & DelVecchio, 2000). Genetic stability increased from moderate in infancy to near perfect by age 30, and remained near perfect across adulthood. Environmental stability (uncorrected), in contrast, displayed almost complete instability in childhood, but increased to about half as stable as genetic influences by adolescence. Correcting for measurement error, environmental stability was weak in early childhood, increased with age, and peaked at a level only slightly less than that of genetic stability. Additionally, we found that genetic influences contributed to phenotypic stability at a relatively stable rate. In contrast, environmental contributions to stability changed substantially with age and accounted
