Do you have a smart device or smart assistant on your phone? If you also have a pet dolphin, you might need to keep an eye on your shopping lists. Since some dolphin chatter is inaudible, Flippy may have been ordering tuna without you noticing.
Researchers at the SSSLab in China have worked out how to use completely inaudible voice commands to activate smart devices and assistants. The commands are inaudible to humans because they are very high frequency sounds. Humans can hear stuff in the range between 20 Hz to 20 kHz, but we are especially attuned to sounds between 1-4kHz. Dolphins, and slightly more worryingly, your smart assistant, can “hear” sounds at higher pitches.
The researchers took voice commands, converted them to > 20kHz to make them inaudible, and played them to various systems. They found that they could get smartphones and devices to obey the secret commands (sadly, not “order 3,000 cans of tuna”, but it’s the same principle …).
This inaudible approach is distinct from messages hidden in audible music (see also subliminal priming). Since it’s physically impossible for you to hear the dolphin commands, you will have no idea, either on a conscious or subconsious level, that the order has been placed.
Your best option to avoid enormous tuna-based bills is to disable voice commands for your smart assistant, or at least disable the “listen-while-locked” functionality. Or rehouse that pet dolphin.