perception question

[Faith L Florer]

Does anyone here know why it is that the numbers on a digital clock (and
some images on a television screen) appear to jiggle when a person is
using an electric toothbrush? 

I was asked this question in cognition class.

Thank you.

Faith Florer

Faith Florer, Ph.D., Adjunct Asst. Professor Marymount College and NYU.
http://www.river.org/~flf/Faith.html