Take a coffee cup (with a side handle). Hold it level in front of your eyes, and rotate it slowly around the vertical axis (in either direction).
You can tell the way it’s rotating because you see the handle coming into view in front of the cup on one side, and disappearing behind the cup on the other. Inferring the direction of spin from that is easy.
However, if the cup was covered in a magic paint which absorbed all visible light, you would no longer be able to make that distinction. What would you see? You’d see the handle shrinking and growing, alternately to the left and right. This would be ambiguous as to the direction of spin.
The dancer is the same, only more detailed, and because your brain infers a whole 3-D anatomy to go with the inferred direction of motion, it’s hard to let go of the conviction that this made-up story about the direction is the “right” story.
Your brain is working perfectly fine, it just wants things to be one way or the other, rather than uncertain.
Yeah, at an intellectual level I understand all that… but it doesn’t make it feel any more intuitive.
And I’m still curious as to whether there’s any significance to which way a person sees it. And why my preferred direction changed after being away from it for awhile (I’m still stuck on left, if anyone’s keeping score)
Susceptibility to priming effects? My intuition says handedness should have little to do with it, and the initial direction perceived by someone not familiar with the illusion would be evenly distributed, BUT people would differ more characteristically in their propensity to see it both ways.
Take a coffee cup (with a side handle). Hold it level in front of your eyes, and rotate it slowly around the vertical axis (in either direction).
You can tell the way it’s rotating because you see the handle coming into view in front of the cup on one side, and disappearing behind the cup on the other. Inferring the direction of spin from that is easy.
However, if the cup was covered in a magic paint which absorbed all visible light, you would no longer be able to make that distinction. What would you see? You’d see the handle shrinking and growing, alternately to the left and right. This would be ambiguous as to the direction of spin.
The dancer is the same, only more detailed, and because your brain infers a whole 3-D anatomy to go with the inferred direction of motion, it’s hard to let go of the conviction that this made-up story about the direction is the “right” story.
Your brain is working perfectly fine, it just wants things to be one way or the other, rather than uncertain.
Yeah, at an intellectual level I understand all that… but it doesn’t make it feel any more intuitive.
And I’m still curious as to whether there’s any significance to which way a person sees it. And why my preferred direction changed after being away from it for awhile (I’m still stuck on left, if anyone’s keeping score)
Susceptibility to priming effects? My intuition says handedness should have little to do with it, and the initial direction perceived by someone not familiar with the illusion would be evenly distributed, BUT people would differ more characteristically in their propensity to see it both ways.