To date, little is known about what interventions can help individuals attain leadership in organizations. To address this knowledge gap, we integrate the communication and leadership literatures to test debate training as a novel intervention for leadership emergence. We propose that debate training can increase individuals’ leadership emergence by fostering assertiveness, a valued leadership characteristic in US organizations. Experiment 1 was a three-wave longitudinal field experiment at a Fortune 100 US company. 471 individuals were randomly assigned to either receive a 9-week debate training or not. 18 months later, the treatment-group participants were more likely to have advanced in leadership level than the control-group participants, an effect mediated by increased assertiveness. In a sample twice as large (N = 975), Experiment 2 found that individuals who were randomly assigned to receive debate training (vs. non-debate training or no training) acted more assertively and had higher leadership emergence in a subsequent group activity. Results were consistent across self-rated, group-member-rated, and coder-rated assertiveness. Moderation analyses suggest that the effects of debate training were not significantly different for (a) US-born and foreign-born individuals, (b) men and women, or (c) different ethnic groups. Overall, our experiments suggest that debate training can help individuals attain leadership by developing their assertiveness.
