Words matter — but your hands might matter more, according to a new UBC study which found that purposeful hand gestures can make speakers appear more competent and persuasive.
The Sauder School of Business research , analyzed 2,184 TED Talks using AI and automated video analysis. Researchers isolated more than 200,000 hand gestures into 10-second clips and compared them against audience engagement metrics, such as 'likes' on social media while controlling for factors like gender, occupation, language, video length and more.
The team also ran randomized experiments in which participants watched videos of sales pitches where speakers delivered identical scripts but varied their hand movements. Viewers then rated the speakers and the products being pitched.
The verdict: More hand movement can significantly boost impact — but not all gestures are created equal.
Winning gestures
Researchers categorized gestures into types, including "illustrators," which visually depict spoken content, for example, demonstrating the size of a fish while describing it, and "highlighters," such as pointing to an object mentioned in the speech. They also examined random, unrelated movements and the absence of gestures.
Illustrators had the strongest effect, making speakers seem more knowledgeable and improving audience understanding. Highlighters and random gestures, however, showed little to no impact.
"Illustrators can help make the content easier to understand because we're delivering the same information in two modes: visual and verbal," explains Dr. Mi Zhou, study co-author and UBC Sauder assistant professor. "When people use illustrators, it increases viewers' perception of the speaker's competence."
According to Dr. Zhou, audiences interpret illustrative gestures as a sign of mastery. "If a person uses their hands to visually illustrate what they're talking about, the audience perceives that this person has more knowledge and can make things easier to understand," she said.
AI decodes the powers of persuasion
While previous research has explored speech patterns and facial expressions, this is the first study to examine hand gestures at scale. Advances in AI made this possible: the team used 21 key points on the hands to calculate hand movement in videos, classified gestures and then linked them to spoken content using multimodal AI, a type of artificial intelligence that can simultaneously analyze multiple types of data.
The findings have implications for marketers, influencers and anyone trying to persuade an audience. "One of the key takeaways for marketers is that you can use the same content, but if you pay more attention to how that content is delivered, it could have a big impact on persuasiveness," said Dr. Zhou.
The research could also help companies design more lifelike virtual assistants and AI-generated characters by pairing verbal communication with natural hand movements.
"Sometimes we just move our hands without a purpose. It's a habit," said Dr. Zhou. "But if you pay more attention and understand the impact, it can make a big difference."
The study was co-authored by Dr. Giovanni Luca Cascio Rizzo of the University of Southern California and Dr. Jonah Berger of the University of Pennsylvania.
