This paper uses data from the random classroom assignment sample of the China Education Panel Survey to examine the spillover effects of classmates' siblings' gender composition on students' outcomes. We find that a higher proportion of female siblings among classmates is associated with significant improvements in students' academic performance, cognitive skills, and non-cognitive skills. These results remain robust after accounting for potential reflection problems and omitted variable concerns. We further explore the underlying mechanisms and show that students' effort and learning attitudes serve as key mechanisms through which the gender composition of classmates' siblings generates spillover effects, with student diligence playing a particularly central role. In addition, explanatory power analyses indicate that students' effort and learning attitudes account for a substantial share of the observed effects. This study provides a new perspective for understanding the impact of gender composition on human capital accumulation.

Non-cognitive skills are the important human capital. Many studies have examined the impact of early experience on non-cognitive skills, but there is a lack of research based on childhood rural experience. Using the China Family Panel Studies data in 2010, this paper investigates the impact of childhood rural experience on non-cognitive skills. The baseline results find that the non-cognitive skills of the group with childhood rural experience is 0.098 standard deviation higher than that of other groups, and the conclusion is robust after using Treatment Effects Model and Propensity Score Matching methods to deal with endogenous problems. Considering the measurement error of non-cognitive skills, this paper uses locus of control, and the conclusion is robust. Further analysis finds that the mechanism by which childhood rural experience can improve non-cognitive skills lies in the efforts made by individuals to adapt to poor environment. In addition, this paper investigates the impact of childhood rural experience on five and thirteen factors of “Big Five”, and finds that the groups with childhood rural experience are higher in agreeableness and extraversion. More specifically, the groups with childhood rural experience are higher in terms of organization, enthusiasm, openness and action, but lower in terms of prudence and value. From the perspective of childhood rural experience, the conclusion of this paper provides empirical evidence for the influence of early life experiences on non-cognitive skills.