Researchers just proved why it's so scary that digital assistants are always listening

As if we needed more reasons to be freaked out by increasingly powerful digital assistants, there's a new nightmare scenario: The music you listen to or conversations you hear on TV could hijack your digital assistant with commands undetectable to human ears. 

This is known as a "Dolphin Attack" (because dolphins can hear what humans can't), and researchers have been aware of the possibility for years. The basic idea is that commands could be hidden in high-frequency sounds that our assistant-enabled gadgets can detect, but we are unable to hear.