What the research found
A study from UC Berkeley and ICSI surveyed 116 owners of Amazon and Google smart speakers, grounding the questions in each participant’s own saved recordings rather than asking about the topic in the abstract. Around 56 percent didn’t know their recordings were stored for good and could be reviewed later. A quarter had ever gone back to review their own interaction history, and few had ever deleted anything. The finding was notable enough to win a best paper award at a major privacy research conference.
People weren’t equally relaxed about every kind of recording. Participants didn’t see their own voice recordings as especially sensitive as a rule, but they were far more protective of recordings involving other people, children and guests in particular, and opposed to any of that data being used by third parties or for advertising. More than 72 percent found it acceptable for a computer to review recordings, while human review of the same recordings felt far less acceptable to most participants.
A separate 2025 survey of 1,103 German smart speaker owners found the underlying problem hasn’t gone away. Existing privacy settings still don’t cover what users want, and the study found a consistent, cross-brand desire for more transparency and more control over what gets collected in the first place.
Why “always listening” isn’t quite the right way to think about the risk
The real privacy gap here is default retention paired with low visibility, not secret eavesdropping. These devices are built to keep what they record unless you go find it and delete it, and most owners never do, because reviewing recordings takes effort most people never think to make, not out of indifference. Following the original 2019 study, both Google and Amazon added auto-deletion options: Google’s set to clear recordings after 3 or 18 months, Amazon’s after a rolling window, evidence that the research pushed real product changes.
The practical takeaway
Check your smart speaker’s privacy settings rather than assuming a sensible default is in place. Both major platforms let you set recordings to delete on a schedule, and it takes a couple of minutes to turn on. Given how much more protective people are of recordings involving guests and children, it’s worth being deliberate about where these devices sit in your home: kitchens and living rooms carry more incidental exposure than a bedroom or office.
Manufacturer defaults and policies shift over time, and what’s true about retention settings today may change. Checking your specific device’s current settings is more reliable than any general description of how these systems work.
References
Malkin, N., Deatrick, J., Tong, A., Wijesekera, P., Egelman, S., Wagner, D. “Privacy Attitudes of Smart Speaker Users.” Proceedings on Privacy Enhancing Technologies, 2019. https://petsymposium.org/popets/2019/popets-2019-0068.php
Hernández Acosta, L., Reinhardt, D. “Alexa, how do you protect my privacy? A quantitative study of user preferences and requirements about smart speaker privacy settings.” Computers & Security, 2025. https://www.sciencedirect.com/science/article/pii/S0167404824006084
