Boosting Persuasion : The Attention Benefits of Multiple Narrating Voices

We report on an investigation of the impact of voice numerosity in marketing videos, specifically product introduction videos and video advertisements, on consumer behavior. Despite the ubiquity of video advertising, the role of voice numerosity as a strategic design element to enhance persuasiveness had not been examined. We analyzed large-scale real-world datasets on crowdfunding and video advertising, using machine learning and econometric models, alongside carefully designed laboratory experiments to isolate psychological mechanisms. We found that the persuasive power of a marketing video is significantly enhanced when employing more narrators, particularly for simpler messages. This "voice numerosity" effect likely occurs because multiple narrators draw consumers' attention to the spoken message, exerting consistent and economically significant effects on various downstream behaviors, including likelihood of purchase and persuasiveness. Our research suggests that the mere addition or subtraction of voice actors can significantly impact consumer attention and processing of the product message, ultimately influencing consumer behavior. For more challenging product messages, a single narrator may be more effective, while for simpler messages, multiple narrators can leverage the voice numerosity effect. These findings offer valuable recommendations for marketing practitioners and consumer information environment architects. Additionally, our methodology presents a novel approach for data exploration and analysis in the social sciences, benefiting from recent advances in neural networks, machine learning, and the increased availability of computational resources