Research

Abstract: Can legal reforms shift social norms, and what are the underlying institutional reasons? This paper shows that severe fertility control policies in China impacted fertility norms across generations. We overcome the difficulty of measuring social norms regarding fertility using a well-designed vignette experiment in a large-scale survey. We establish policy causality through a cohort-province difference-in-differences framework. The policy's effect reflects the dismantling of Confucian fertility culture, with greater impact in regions with stronger historical Confucian symbols. The institutional reason lies in top-down bureaucratic force, grounded in loyalty culture and political enforcement. We rationalize the findings by a social-norm equilibrium framework.

Abstract: This paper examines whether markets respond to superior information or the psychological weight of coordinated action when multiple insiders trade together. In the context of China's A-share market, I introduce a ``silence window'' to identify initiating trades free from recent insider activity. Collective purchases (sales) generate substantially stronger positive (negative) cumulative abnormal returns than individual trades. The amplification for purchases is most pronounced in firms with weak monitoring and when participating insiders are junior, short-tenured, or small shareholders—profiles perceived to act only on especially strong private information. For sales, the opposite pattern emerges: effects are largest in well-monitored firms and when trades involve senior executives, long-tenured insiders, or large shareholders, whose exits are viewed as high-credibility warnings. I develop a theoretical framework that endogenizes insider coordination, outsider composition, and credibility channels, yielding predictions that distinguish superior-information from psychological-signal channels.