Do shining stars cast shadows on others? Investigating the effect of star centrality on shared leadership

• Team star centrality negatively influences shared leadership in teams. • Leadership-related underdog expectations of nonstars is an important mediator. • Star centrality's influence is stronger in teams with low cognitive diversity. Research has identified formal leaders and team characteristics as the two primary antecedents of shared leadership. However, little insight has been provided into the role of specific team members, despite the fact that some team members can have a disproportionate influence on others. Drawing from adaptive leadership and social comparison theories, we propose that star centrality is negatively related to shared leadership via nonstars’ leadership-related underdog expectations. We posit these direct and indirect effects are moderated by team cognitive diversity. Two field studies were conducted using time-separated, multisource data to test these team-level hypotheses. Results showed that star centrality has a negative direct effect on shared leadership and a negative indirect effect on shared leadership via nonstars’ leadership-related underdog expectations. These direct and indirect effects are strengthened under conditions of low team cognitive diversity. Theoretical implications about how star centrality can affect shared leadership are provided, followed by practical recommendations.