With the view toward improving the racial diversity in organizations, this work seeks to uncover the reasons why larger groups have an advantage in terms of job opportunities. Based on people’s preference for diversity in commodity selection, we propose a potential feature that may exist in human resource management and call it the isolated choice effect, which unconsciously affects the racial diversity of organizations. Specifically, when making selections in isolation, people are less likely to choose the one whose race would (...) increase group diversity than when making selections in collections. We set up eight experiments in which participants make hiring or firing decisions among choices that are more white people than black people. We find that participants in the isolated choice group are less likely to choose black people, the smaller group, than those in the collective choice group. Our results show a potentially important contributing factor to the underrepresentation of black people in many organizations because hires are often made in isolation while layoffs are often made in collections, which provides a starting point for improving racial diversity in organizations by avoiding the isolated choice effect. (shrink)