Summary: Prosody is important in human communication, and potentially for human-machine communication. This is true especially as we move towards more collaborative modes of human-AI interaction, but its value for this has not been systematically measured. To investigate, we created an AI player for a collaborative game, which communicated with human players in four conditions: with and without appropriate prosody, and with and without lexical content. Players rated the four versions in terms of trustworthiness and other measures, and described when and why they felt their trust in an agent had increased or decreased. Prosody was judged to contribute around 25% of the value of the entire speech channel, depending on various factors, especially individual preference variation. Prosody was noted to be important specifically for functions including warning, instructing, and encouraging.
Experiment testbed: (play the game yourself!) The key conditions are "monotone" and "full audio".
Results: spreadsheet
Slides: [pending]
Experiment Videos.