Functional accounts of hierarchy propose that hierarchy increases group coordination and reduces conflict. In contrast, dysfunctional accounts claim that hierarchy impairs performance by preventing low-ranking team members from voicing their potentially valuable perspectives and insights. The current research presents evidence for both the functional and dysfunctional accounts of hierarchy within the same dataset. Specifically, we offer empirical evidence that hierarchical cultural values affect the outcomes of teams in high-stakes environments through group processes. Experimental data from a sample of expert mountain climbers from 27 countries confirmed that climbers expect that a hierarchical culture leads to improved team coordination among climbing teams, but impaired psychological safety and information sharing compared with an egalitarian culture. An archival analysis of 30,625 Himalayan mountain climbers from 56 countries on 5,104 expeditions found that hierarchy both elevated and killed in the Himalayas: Expeditions from more hierarchical countries had more climbers reach the summit, but also more climbers die along the way. Importantly, we established the role of group processes by showing that these effects occurred only for group, but not solo, expeditions. These findings were robust to controlling for environmental factors, risk preferences, expedition-level characteristics, country-level characteristics, and other cultural values. Overall, this research demonstrates that endorsing cultural values related to hierarchy can simultaneously improve and undermine group performance.hierarchy | culture | groups | coordination | psychological safety H ierarchy helps groups conquer many of the challenges and threats that they face. For example, hierarchical differentiation can increase group performance by clearly defining roles that facilitate coordination (1) and the integration of information (2, 3) and by creating patterns of deference that reduce intragroup conflict, especially when group members are interdependent (4, 5).Hierarchy, however, also has the potential to kill. Rigid hierarchies limit low-ranking group members from voicing their opinions and concerns. This lack of participative voice can produce negative outcomes, including greater mortality (6, 7). Hierarchy can also reduce feelings of psychological safety (8), thereby impairing group communication (9) and performance (10). In contrast, when hierarchies allow lower ranked individuals to speak up and share relevant information, groups can effectively identify critical errors and prevent them from having adverse consequences (11).The above research suggests that hierarchy can produce both the best and the worst outcomes for groups and organizations. Our research seeks to establish the dual role of hierarchy by drawing on experimental data from an international sample of expert mountain climbers and over 100 y of archival data from mountain-climbing expeditions in the Himalayas. We show that expert climbers believe that the cultural value of h...