Facebook does not use your phone's mic to spy on conversations, inform ads, or change News Feed content, the company insists.
"Some recent articles have suggested that we must be listening to people's conversations in order to show them relevant ads," Facebook writes in a blog post. "This is not true."
The social network's ads are based on users' interests and other profile information—"not what you're talking out loud about," the notice said.
The Independent, however, last week interviewed University of South Florida mass communication professor Kelli Burns, who told the newspaper that she tested the theory by talking about specific topics within earshot of her phone, then found relevant ads on Facebook. It's possible, of course, that Burns had recently searched for the same subjects. But, she told the Independent, it "wouldn't be a surprising move" from Facebook.
"We only access your microphone if you have given our app permission and if you are actively using a specific feature that requires audio," Facebook says.
That includes recording a video, or using the optional feature introduced two years ago to share and discover entertainment by using your phone's microphone to identify what song is on the radio or which show or movie is playing. When the function launched in May 2014, Facebook ensured users that "no matter how interesting your conversation," it would not store sound or recordings.
"If you choose to turn this feature on, it will only use your microphone (for 15 seconds) when you're actually writing a status update to try and match music and TV," the company said at the time.