Adult-proof ringtones plague classrooms

You know how kids often have selective hearing when it comes to instructions like “clearing up the room” and “taking out the garbage”? Similar in concept to the dog whistle, “adult-proof” ringtones are often high-pitched tones that remain silent to a pair of aged ears. Students are already utilizing this biological loophole to avoid being caught by teachers while sending text messages to each other in class. If you want to see if your ears are still up for it, check out a sample ring tone here.