If you’ve been left feeling paranoid after your phone has displayed an advert of a random item you’ve just been speaking about, you’re not alone. From throwing up an ad of a new food item, or a random household product, it can leave you feeling spooked if you’ve just been discussing it with a friend.
And although social media platforms have long denied snooping on their users, new research suggests companies are using a sneaky type of data monitoring systems that are using the devices’ microphone systems to their advantage. The research from NordVPN says companies are using ultrasonic cross-device tracking to listen to background noise and serve up personalised ads, while of course charging the company for the pleasure.
According to NordVPN, this cross-device tracking method sees apps use ultrasonic ‘audio beacons’ which can’t be heard by the human ear to ‘link all the devices you own to track your behaviour and location’. These high-pitched signals can be hidden in TV adverts or online videos.
Once your device microphone picks them up, it gives advertisers the ability to identify what you’ve just been watching or talking about. Different apps on your phone can listen for these beacons to keep an eye on what you’re doing—and this is why some apps ask you for permission to access your microphone.
NordVPN’s study found that almost half of Brits (45%) claim to have seen an ad for something appear on their phones soon after talking about it or watching it on TV, without ever searching for it online themselves. Meanwhile, 62% of consumers said they had no idea how to prevent this and a further one in eight people said the adverts ‘scared’ them.
Is my phone listening to me - how to stop it
NordVPN’s Adrianus Warmenhoven said: "While it’s impossible to stop the ultrasonic beacons working, you can reduce the chance of your smartphone listening for them by simply restricting unnecessary permissions you have granted the apps on your device."
NordVPN says turning off microphone access to apps that don’t need it could help. To change the permissions apps have, you can go to your phone’s Settings menu and look for a ‘Privacy’ option. Here you should be able to see which apps have access to your microphone and limit it where necessary.
Alternatively, you can use a secure browser like Brave, Tor, or DuckDuckGo—or get a VPN, which encrypts all of your online activity.