Why do digital things bounce up and down when you eat something crunchy and other things do not?

Dear Matthew Alice:

Try this: Eat something crunchy (such as corn chips) while staring at a digital clock (such as on a microwave). The numbers bounce up and down! Why is this? And why don't other objects bounce up and down when you eat crunchy food things?

-- Lisa Urmston, Mira Mesa

The elves say that for entertainment value it will never replace Nintendo. But they sat on the kitchen counter and crunched for a while, until Grandma shooed them off. Can we assume you were waiting for the nacho sauce to heat up when you discovered this, Lisa? Anyway, we dialed up Dr. Peepers, our staff eyeball checker, and he filled us in on the reason why. Seems that when we chew, especially something crunchy, vibrations go through our head bones and jiggle our eyes. Light zinging into our eyeballs is trying to hit a moving target, so it registers on our retinas at slightly different locations. Which also explains why you can't jog and study for an exam at the same time. But wait, there's more. A digital display appears to be steady light, but it actually flickers like a fluorescent bulb. So the jumpy light and your vibrating retinas combine to make the numbers appear to hop around. If you're willing to spend hours every day eating Fritos and staring at the microwave, Dr. Peepers says your brain eventually would compensate for slight movement and the numbers would sit still. Then the only question is whether boredom, indigestion, or a big old headache would get to you first.