From the Skrufff mailout:

British police are backing a new anti-teenage delinquent device which torments young people by emitting high frequency screeches which are inaudible to almost everyone older than 20.

The ‘Sonic Teenager Deterrent’ broadcasts 80-decibel bursts of sounds at 16khz and is being tested at locations where teenagers loiter, forcing them to scatter while leaving adults entirely unaffected, said the Daily Telegraph.

“The frequency at which it operates is at the very limits of our hearing and will be heard only by youngsters. It is like when people are young they can hear the noise of bats but not when they are older,” said Angela King, an audiologist from the Royal National Institute for the Deaf.

“Over the years, cells in the inner ear die or are damaged and the ones that go first are the ones that hear higher frequencies.”

The fiendishly clever device, which costs £622 (AU$1470), is being used in Rochdale and Manchester while in London, tube station operators are about to start broadcasting classical music to ‘reduce stress levels’ on the system, or to ‘reduce antisocial behaviour’ as the Guardian saw it.

“The bits of the brain below the cerebral cortex that are hot-wired to our senses detect potentially threatening stimuli and ready the body for action. That’s why if you hear a loud sound, you jump,” Cambridge University music don Dr Ian Cross told the paper.

“Classical music generally - but not always - has a continuous, organised sound level and so is less likely to activate that part of the brain in that way.”