Older Siblings' Contributions to Young Child's Cognitive Skills.

This work finds that older siblings as well as early parenting influence young children's cognitive skills directly or indirectly, for example, Mathematics, and English. Our findings challenge a pervasive view in the economical literatures that early parenting play a dominant role in explaining child development. In economics, early environmental conditions are important to demonstrate the evolution of adolescent and adult cognitive skills (Knudsen, Heckman, Cameron, and Shonkoff, 2006; Cunha and Heckman, 2007), and it establishes causal impacts of early parental inputs and other environmental factors on cognitive and non-cognitive skills (Heckman, Stixrud, and Urzua, 2006; Borghans, Duckworth, Heckman, and Weel, 2006; Cunha, Heckman, and Schennach, 2010). Early parenting as well as older siblings should explain a diverse array of academic and social outcomes, for example, Mathematics, English, maritage and pregnancy. In fact, older siblings' characteristics are as important, if not more important, than parenting for child development. Our analysis addresses the problems of measurement error, imperfect proxies, and reverse causality that plague conventional approach in psychology. We find that older brother contributes much more than older sister to child's mathematical achievement, while older sister contributes much more to child's english achievement. Our evidence is consistent with psychology literature, for example, Hetherington (1988), Jenkins (1992), Zukow-Goldring (1995), Marshall, Garcia-Coll, Marx, McCartney, Keffe, and Rub (1997), Maynard (2002), and Brody Ge, Kim, Murry, Simons, Gibbons, Gerrard, and Conger (2003) for siblings' direct contributions to child development, Bronfenbrenner (1997), East (1998), Whiteman and Buchanan (2002), and Brody, Ge, Kim, Murry, Simons, Gibbons, Gerrard, and Conger (2003) for siblings's indirect contributions, and Reiss, Neiderhiser, Hetherington, and Plomin (2000), Feinberg and Hetherington (2001), Kowal, Kramer, Krull, and Crick (2002) for parental differential treatment.