Answer Geek:How Chewing Affects TV Flicker

<br> -- Q U E S T I O N: About the chewing flicker, it happens to me and I have braces. Maybe the magnetic field? — Ted Q U E S T I O N: In your screen flicker article about chewing and the screen doing funky things, I have noticed a similar phenomenon when I cough. Could it have something to do with pressure on the eyes? — Bill B. Q U E S T I O N: This isn’t a question, but the flickering effect seen when chewing gum can be simulated if you do a raspberry, like you would on a trumpet. I think you might have to be some distance away. I would try it now but I don’t want to look like an idiot at work. — Anthony

A N S W E R: When I added the little bit at the end of last week’s column dismissing the notion that there was any relationship between chewing and flickering computer monitors and television sets, I had no idea I was tapping into one of the great untold technology mysteries of the modern era.

Torrent of E-Mail

The question, and my rather flip response, unleashed a torrent of e-mail. It turns out that people all across the country are chomping on chips and wondering why it’s making the display unit they are looking at do strange things. An unprecedented number of you wrote to set me straight and share your theories — I received more messages in the first hour after that column went live than I usually get in a week, and more over the course of the week than I normally get in a month. (People also vigorously e-mailed ABCNEWS.com with comments and explanations.)

Not only are you chomping on chips (Doritos seem to be the favorite), you are chewing on ice, crunching on candy, clacking their teeth together, blowing raspberries, shaking your head, blinking quickly, and brushing your teeth with an electric toothbrush, all while watching TV or sitting in front of the monitor. Then there are the people who see the flicker while resting their head against a stereo speaker or while using one of those handheld electric massagers. A couple people wrote to say they can see the flicker if they hum very low notes. I even heard from someone who recommended sticking a Popsicle stick between my teeth and “boinging it like a diving board” in order to recreate the phenomenon.

Putting to Bed the Myths

So let’s start by getting some of the wackier theories out of the way. I can report with a great degree of confidence that it has nothing to do with electric fields produced by braces, but thanks for writing, Ted. Coughing is not the cause, either. Nor is it caused by astigmatism, wearing glasses, or hard contact lenses, or the color of your eyes, although I can’t entirely rule out the possibility that any of those situations may make it easier to perceive said flicker.