Stumbled across some more neat optical illusions.

Here’s one created by M Bach & J L Hinton.

If your eyes follow the movement of the rotating pink dot, you will only see one color. Pink. If you stare at the black + in the center, the moving dot turns to green. Now, concentrate on the black + in the center of the picture. After a short period of time, all the pink dots will slowly disappear, and you will only see a green dot rotating. The image is a 12-frame gif file of a circle of pink dots with a single one missing in rotation from each frame. There are no green dots. There are no frames with any more than one pink dot missing.

With this one, focus on the black dot in the centre and then move your head in towards the screen and away again. No changing frames in this illusion. It’s a static image.

Which way is the dancer turning? Clockwise or anticlockwise?

According to the Perth News site which this image originally appeared on, if you see her spinning anticlockwise then you tend to have your left brain functions predominating. A clockwise spin indicates more of a right brain dominance.

The left side of the brain is associated with processing that is logical, detailed, factual, practical, reasoned, linear, sequential and expressed in language. It controls the right (L. dexter) side of the body. The right side deals more with processing that is intuitive, non-verbal, imaginary, holistic, random, symbolic, relational, philosophical, and spatial, controlling the left, (L. sinister) side of the body.

Rather than being any indication of brain functioning dominance however, logic would say this is just a simple, though very nicely executed, optical illusion which calls on the same image and spatial interpretation functions in the brain regardless of which way we see the dancer turning. The image has been doing the rounds for a few months now. Most people responding in comment sections seem able to make the dancer change direction at will after a bit of practice, and most seem to see her rotating clockwise initially.

What I find more interesting than any putative brain dominance diagnosis is the number of comments from people utterly convinced the dancer’s change in direction is programmed into the image file and that the whole thing is a fraud. It’s not – it’s just a 34-frame animated gif which cycles through the images (anticlockwise) in a continuous loop – but it shows very nicely the extent to which we’re willing to believe reality is “out there” rather than constructed in our heads.

(Occasional stutters in the image rendering can be sufficient to break the illusion and ’cause’ the dancer to ‘change direction’, but it’s all in the brain.)

“All life is only a set of pictures in the brain, among which there is no difference betwixt those born of real things and those born of inward internal dreamings, and no cause to value the one above the other.”
H P Lovecraft