Our meta-analysis is particularly innovative in its ability to draw inferences about the developmental trends in the genetic and environmental sources of stability across close to the entire lifespan. Previous studies have provided insights into specific periods of development, but no individual study has been able to plot trends in genetic and environmental stability from birth to near the end of the lifespan. By combining studies of circumscribed periods of development, we were able to make several novel insights into personality development across much longer periods than those examined in the individual studies. Phenotypic, genetic, and environmental stabilities of personality increase substantially in the first three decades of life. Likely the most innovative and surprising finding of the current analysis is that the genetic contribution to stability remains relatively constant across the lifespan compared to the large increases in environmental contributions to phenotypic stability.
