Pardon me if this is a repeat, but I don't think I sent this to the whole list. (At least judging from the continuing speculation.)
Not being an electric toothbrush user, this is a guess, but an educated one. Motion of the eye that is produced via the normal eye control system (including head movements, etc) are interpreted as eye moving, and world stationary. Movement of the eyes produced through other channels ((pushing on the eye (through the lid) with the finger, etc) is interpreted as produced by movement of the world. v. Holst has a theory to explain this (reafferent information results from self produced motion , whereas exafferent information is from movement of the world) in feedback terms. The arm-toothbrush is not part of the buuilt in feedback mechanism. The same principle explains why you cant tickle yourself. don Donald McBurney Faith L Florer wrote: > 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
