Facebook has been listening to US users of its apps since 2014, but a recent report from The Independent claims that the social network is always listening. Kelli Burns, a communications professor at the University of South Florida, told the paper that she believes Facebook listens to all conversations people have while the app is open, to serve more relevant ads to those people by listening to what they’re talking about.

The social network, however, tells Quartz that it only accesses a user’s microphone—assuming they’ve given it permission—under very specific circumstances, such as when they’re recording a video or asking it to listen to music on the television. Facebook also published a blog post today reassuring users that it doesn’t use audio recordings for ad-targeting purposes.

But if you want to revoke Facebook’s access to your microphone anyway, here’s what you do:

On iPhone (iOS 9)

Go to the Settings app Scroll down to Facebook, tap it Tap “Settings” Turn off the slider for Microphone (slider should be grey instead of green)

On Android (Marshmallow)

Go to Settings Swipe over to “Personal” Tap “Privacy and safety” Tap “App permissions” Tap “Microphone” Find Facebook, and turn the slider to OFF

Facebook made over $5 billion in sales last quarter, and the vast majority of its revenue comes from advertising. Even if it’s not listening to us, it reads what we post: Just yesterday, the company announced a new AI program that effectively helps the company to figure out exactly what users are saying in their posts, which Facebook could eventually use to show users more relevant ads.