Self-Persuasion: Evidence from Field Experiments at International Debating Competitions

Laboratory evidence shows that when people have to argue for a given position, they persuade themselves about the position's factual and moral superiority. Such self-persuasion limits the potential of communication to resolve conflict and reduce polarization. We test for this phenomenon in a field setting, at international debating competitions that randomly assign experienced and motivated debaters to argue one side of a topical motion. We find self-persuasion in factual beliefs and confidence in one's position. Effect sizes are smaller than in the laboratory, but robust to a one-hour exchange of arguments and a tenfold increase in incentives for accuracy.

Automated summary

Laboratory evidence suggests that people tend to persuade themselves about the factual and moral superiority of a given position when they have to argue for it, which limits communication's potential to resolve conflict and reduce polarization. A field study conducted at international debating competitions confirms this self-persuasion phenomenon in factual beliefs and confidence in one's position. Although effect sizes are smaller than in laboratory settings, they remain robust even after a one-hour exchange of arguments and a significant increase in incentives for accuracy.