Michael,
I think the optimal strobe to elicit a seizure is somewhere between 10-30
Hz, though some epileptics report being bothered by florescent lights. I'm
not sure about Hz of computer screen combined with moving fingers. (Once
read that children, who are more photosensitive than adults, sometimes
elicit a "different state of consciousness," by waving fingers between
their eyes and a light source to create flicker.)
Another interesting flicker fusion phenomenon (succession of discrete
stimuli being fast enough to appear continuous)--
1. If you look straight ahead at the computer screen > no flicker. (If
there is flicker, you can adjust the brightness/contrast to eliminate.)
2. Now turn your slightly to the side & look at the screen from the corner
of your eye > flicker.
My hunch: the cycles/sec (Hz) for the rods (peripheral vision) needs to be
higher for fusion, compared to the lower flicker fusion rate for the
cones (central vision).
This phenomenon is just something I noticed. TIPsters, if it doesn't happen
for you, or if you have a another explanation, please post..
Karin Hu, Ph.D.
City College of San Francisco
At 02:30 PM 3/13/99 -0600, Michael Hulsizer wrote:
>Tipsters,
>
>I hava (tequila anyone) question from a colleague. Why is it when
>one shakes a finger in front of the computer screen, you see a
>series of discrete images...much like a strobe light. Yet if you
>shake it in front of a white wall...it appears continuous?
>
>We believe the answer is due to the refresh rate of the screen.
>The cathode ray is redrawing the pixels at a the rate of around 75
>Hz. I imagine you would get the same effect with a florescent
>light (60 Hz) but not an incandescent light.
>
>Does this sound correct?
>
>Now that the entire list is shaking their fingers at their computer
>screen (Simon Says?)...I have an additional question. Would this
>refresh rate/strobe light effect cause seizures like those reported
>in Japan? Furthermore, might their be a rash of seizures around
>midnight on Dec 31, 1999...when all of our computers freak out!
>EGad!!!! ;-)
>
>Mike Hulsizer - Suffering from March Madness.....
>
>--
>Michael Hulsizer
>Webster University
>
>mailto:[EMAIL PROTECTED]
>
Karin
[EMAIL PROTECTED]
