Truth over falsehood: Experimental evidence on what persuades and spreads.

The English poet John Milton portrayed truth as a powerful warrior capable of defeating falsehood in open combat. The spread of false information online suggests otherwise. Here, we test the persuasive power and transmission potential of true versus false messages in a controlled experimental setting, free from the effects of social media algorithms and bot amplification. Across four experiments (combined N = 4,607), we tested how perceived veracity affects message persuasion and shareability, using messages generated by both humans and large language models. Experiments 1 and 2 (persuasion game) involved participants creating and evaluating persuasive messages; Experiments 3 and 4 (attention game) focused on messages optimized to capture attention. Our findings consistently show that messages created with the intention of being truthful were more persuasive and more likely to be shared than those designed to be false. While perceived message truth was the main driver of persuasion, message transmission was primarily driven by positive emotion and social engagement, indicating that social connection is prioritized during information sharing. These results suggest that truth holds a competitive edge in the marketplace of ideas. (PsycInfo Database Record (c) 2025 APA, all rights reserved).