17
2014
Listen to the scientists and protect your hearing
Its National Science and Engineering Week, and Dr Mike Goldsmith, scientist, acoustician and author, considers how his own history of noise exposure has affected his hearing health, and why we should all listen to scientists when it comes to the effect noise has on our hearing.
As a scientist and noise historian, I have been known to look back with regret to those halcyon days, sometime after the Second World War, during which, when scientists spoke on the media, people listened and nodded appreciatively. “Sounds a bit odd to me” I imagine those listeners muttering (ears pressed to the warm Bakelite of their crackly wirelesses) “but these scientists know a thing or two.” Fast forward to today, and the white-coated expert-who-knows-stuff is not accorded quite such uncritical acceptance (except on toothpaste and shampoo adverts). There are plenty of reasons for this jaundiced view, but one consequence is that pronouncements on noise and the harm it does are apt to be taken less seriously than they should be. And they REALLY should be.
When I was a teenager I was as keen as anyone to give my hearing system a good hammering at the occasional disco or concert - the familiar deadening sensation that followed just being par for the course. Reprehensible of course, and maybe why I have tinnitus today, but not of frequent occurrence - unlike today’s teenagers, many of whom have MP3 players firmly attached for many hours a day. And, once earphones or headphones are in place, a number of unfortunate laws of science leap into action to ruin their owner.
The first such law is that it’s not loudness alone that deafens, it’s also duration. So, a sound which is innocuous if listened to for a few minutes can become injurious if it continues for an hour: and a daily disco in your ear is worse than a monthly trip to a real one.
Secondly, one of the hearing system’s primary jobs is to keep us safe, and it does this by monitoring the sound-field for changes (after all, the ancient bits of your brain point out, that sudden noise might easily be the sabre-tooth tiger). So, while an increase in the volume of a sound automatically alerts us and attracts our attention, if the sound then maintains its level, the hearing system will stop attending to it so closely. So - you’re on a noisy train and you can’t hear your music clearly, you turn it up much louder than normal. Pretty soon you’re used to it, hence loud it stays, even when you’re off the train and somewhere quiet.
Thirdly: we evolved to have bodies which were fit and healthy and functional until our children were old enough to take care of themselves, after which it didn’t much matter if bits of us got flabby, stopped working, or fell out. So - abuse your ears as a teenager, but pay the bill when your older, and the price is deafness. Which in turn means, it’s no good listening to what you ears are telling you when you’re young - listen to a scientist instead. While you still can.
Dr Mike Goldsmith is a freelance acoustician and science writer. His book on the history of noise, “Discord”, was published in 2012.
