  Voice assistants offer a convenient and hands-free way of accessing computing
in the home, but a key problem with speech as an interaction modality is how to
scaffold accurate mental models of voice assistants, a task complicated by
privacy and security concerns. We present the results of a survey of voice
assistant users (n=1314) measuring trust, security, and privacy perceptions of
voice assistants with varying levels of online functionality explained in
different ways. We then asked participants to re-explain how these voice
assistants worked, showing that while privacy explanations relieved privacy
concerns, trust concerns were exacerbated by trust explanations. Participants'
trust, privacy, and security perceptions also distinguished between first party
online functionality from the voice assistant vendor and third party online
functionality from other developers, and trust in vendors appeared to operate
independently from device explanations. Our findings point to the use of
analogies to guide users, targeting trust and privacy concerns, key
improvements required from manufacturers, and implications for competition in
the sector.
