CENTRAL CALI

That is crazy, thanks for posting

ChennaiMR

Check this link for all sorts of Optical illusions with nice technical details

http://www.michaelbach.de/ot/index.html

JDN

Sounds OK to me, Rudy, but I do have one question. Are you sure the pink dots are shutting down? If I don't stare at the center +, the pink dots just keep on keeping on.

Rudy

I don't think the pink dots shut down at the point where you stare at the center and they all disappear. What I'm describing is that one dot turns off then back on right when the next one turns off. In other words, to make the dot spin around the circle, one dot at a time is off in quick succession. After a few seconds, when a pink dot turns off, your retina substitutes a green dot in it's place. That's what makes it look like a green dot is moving around the circle...

JDN

I'll accept that, Rudy. Makes my head hurt to think.

Centurion

Here is what's happening...

The pink dots arranged in a circle are stationary. They don't move. Now, as soon as one flashes off then on, the next one flashes off then on. Just as Rudy described it. This quick succession creates the illusion of movement. Again, nothing is really moving.

Where is the green dot coming from?
As a test, cover all the dots with something except for one of them. You will notice that the pink dot actually doesn't flash "off" as I described above. Instead it flashes "green" for such a brief moment before returning to "pink" again.

Why do I only notice the green dot when I stare at one point?
Light passes through the front of our eyes and is projected to the back part called the retina. The retina of our eyes is composed of specialized photoreceptors called rods and cones. Cones sense only color while rods sense only light. When we look at a subject, that image is focused in an area of our retina that is highly concentrated with cones (fovea centralis). Everything outside of this area is mostly rods (also called the "periphery"). Hence, our fovea centralis picks up this super-quick transition of color when we are focused at the subject or focused somewhere near the subject that changes color. You can stare at any of the dots and notice it will flash green.

Why do some of the pink dots seem to disappear?
This occurs to the pink dots in your peripheral vision. As you are staring at something, that subject is in complete focus, however, without moving your eyes off that subject, you are still able to see things around that subject but a bit blurry...that is what peripheral vision is. Now, the image of some of the pink dots in your peripheral vision are falling into a part of your retina called the optic disk. This area has no rods or cones, hence, no info can be sent to the brain.
As a test, cover your left eye with your left hand. Now stare at the dot at the 9 'o-clock position and move your head closer towards your monitor but very slowly. As you're doing this, do not take your focus off the dot at the 9 'o-clock position. You'll notice that the pink dot on the opposite side of the circle (at the 3 'o-clock position) will disappear (the image is being projected onto the optic disk of your retina). Now, slowly keep moving towards your monitor and it will eventually come into your peripheral vision again.

Rudy

Yeah, like that...

Centurion

LOL!

...and this is really the simplified explaination.

JDN

Uh huh.