Exploring the Impact of Modality and Speech Rate Manipulation in Voice Permission Requests—Limits of Applicability and Potential for Influencing Decision-Making

As voice-enabled technologies are becoming increasingly more prevalent, voice-enabled permission requests become a crucial topic of investigation. It is yet unclear how to appropriately inform users in voice user interfaces (VUIs) about data processing practices. To understand how modality (text vs. voice) and the speech rate of the voice can influence users’ perceptions and decisions to grant permission, we conducted two preregistered studies (N = 343 and N = 594) and one pre-study, including two listening tasks to design potentially deceptive voice patterns. We found that users can distinguish between different levels of intrusiveness in the voice modality. However, they are less likely to accept voice-based permissions, pointing to cognitive problems associated with them. Moreover, we found that speech rate manipulations of action verbs “Accept” and “Decline” shifted users’ decisions towards acceptance, making the effect less controllable than predicted. This work highlights implications and design considerations for future voice-enabled permission requests.