The Shinjiro Thing: A Quasi-Experiment on Social Norm Signaling, Pluralistic Ignorance, and Paternity Leave in Japan

In early 2020, paternity leave uptake among Japanese men was low despite widespread private support. Empirical studies suggest that a misperception underlies this gap: many men believe others are less supportive than they themselves are. While research has shown that institutions can signal social norms, less is known about whether individual actors can do the same, particularly in non-Western contexts. This research tested whether a highly visible counter-stereotypical act by a political elite could shift such perceptions. Drawing on Environment Minister Shinjiro Koizumi’s January 2020 announcement of a two-week paternity leave, two quasi-experiments assessed short-term effects on private attitudes, perceived social norms, and public expression. Study 1 (N = 436; two-wave panel spanning the announcement) found robust evidence of pluralistic ignorance at baseline and no post-announcement change in private attitudes or perceived norms; however, a small, borderline increase in pro-leave opinion expression appeared among those aware of the announcement. Study 2 (N = 537; between-subjects replication after a brief delay) showed no effects on attitudes, perceived norms, perceived directional norms, or willingness to express support. Across studies, pluralistic ignorance persisted. The results suggest little to no immediate norm-updating from a single elite signal in a culturally tight context and only uncertain evidence for short-lived expression change. The findings refine theorizing about when elite behavior conveys normative information and underscore the difficulty of correcting misperceived norms through a single salient event.