A new hand-held gun created by Japanese researchers has a startling capability: It can stop a person from speaking mid-sentence.

The gun works by using the concept of delayed auditory feedback. A microphone attached to the device picks up the words being said — and then plays it back 0.2 seconds later. The human brain, hearing this echo effect, becomes immediately confused and interprets it as silence. The device has no harmful effects.

The researchers say the tool is intended to be used in quiet spaces, such as libraries, to stop people from speaking. But in a published paper, they also seem to have bigger plans in mind:

We have to establish and obey rules for proper turn-taking when speaking. However, some people tend to lengthen their turns or deliberately interrupt other people when it is their turn in order to establish their presence rather than achieve more fruitful discussions. Furthermore, some people tend to jeer at speakers to invalidate their speech.

“In other words,” writes ExtremeTech.com, “this speech-jamming gun was built to enforce ‘proper’ conversations.”

Yahoo notes that there could be implications for free speech if law enforcement or other agencies began using the device at protests or political rallies.

The speech jammer has no effect, however, on meaningless sound sequences, like “Aaaargghhh.”

In Philadelphia, one man has already found a way to silence talkers -- at least the ones talking into their phones. After being caught using an illegal cellphone jammer by a local NBC news affiliate, the man, who calls himself Eric, said: “A lot of people are extremely loud, no sense of just privacy or anything. When it becomes a bother, that’s when I screw on the antenna and flip the switch.”

