  Voice Assistants (VAs) can assist users in various everyday tasks, but many
users are reluctant to rely on VAs for intricate tasks like online shopping.
This study aims to examine whether the vocal characteristics of VAs can serve
as an effective tool to persuade users and increase user engagement with VAs in
online shopping. Prior studies have demonstrated that the perceived tone, age,
and gender of a voice influence the perceived persuasiveness of the speaker in
interpersonal interactions. Furthermore, persuasion in product communication
has been shown to affect purchase decisions in online shopping. We investigate
whether variations in a VA voice's perceived tone, age, and gender
characteristics can persuade users and ultimately affect their purchase
decisions. Our experimental study showed that participants were more persuaded
to make purchase decisions by VA voices having positive or neutral tones as
well as middle-aged male or younger female voices. Our results suggest that VA
designers should offer users the ability to easily customize VA voices with a
range of tones, ages, and genders. This customization can enhance user comfort
and enjoyment, potentially leading to higher engagement with VAs. Additionally,
we discuss the boundaries of ethical persuasion, emphasizing the importance of
safeguarding users' interests against unwarranted manipulation.
