Maybe its just me, but I don’t even see how it could be physically possible for her to be on her right foot
That’s exactly what I thought as well.… except the other way around.
Freaky.
ETA: ok, I just looked at it again, for the first time in several hours, and now I see her on her left foot, and can’t make myself see her on her right foot (opposite of before).
This keeps getting freakier and freakier. I feel like my brain is defective.
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.
I’m having a hard time trying to figure out how to explain the phenomenon I just witnessed. I went back to that link feeling that I might have missed something and I’d give it another try. In the first image she is clearly spinning on her left foot, the same way I always see it. I then look at the second image. Same thing. On the third image, I thought I was seeing it the way I always do, but when I looked at which foot was on the ground, it was her right! Since the foot in the middle never moves except for up and down, I wondered how it could possibly be the same image. So I compared it to the one in the middle to see if it really was the same, and both rotate exactly the same! Every pixel is the same (except the ones with color.) How could this be possible! So I looked back at the first and compared it to the one in the middle. Same thing, every pixel where it should be, and her left foot was clearly the one moving up and down. How could this be! I thought about it and came up with the idea that if the backside was similar enough the the front, you could switch between which side you saw as front/back and left/right would chang accordingly. But this is not the case, they are far to different. I am completely dumbfounded to the physics behind this. Looking at it again, I can focus on the spot between the first and the second and watch them move the same, then switch to focusing on the spot between the second and third, making her suddenly stop and turn the other direction. By switching back and forth really fast, she quickly wobbles back and forth. I begging to wonder if magic is possible.
The backside isn’t just similar to the front, they are both exactly the same shade of black.
This might help you understand what’s going on: if you lie on the ground and have someone trace your outline, you can’t tell from the outline whether you were face up or face down.
Is there a pausible version of this? If I could freeze the individual frames, I might get it. I refuse to believe that her backside is that similiar, because just look at all the detail. Also, the part that reallly bugs me is not her direction of spin, but the fact I can’t even tell which way is right or left.
The Wikipedia entry (link in OP) has a frame-by-frame version. (ETA: or you could download an animated GIF editor, and yourself produce from the ambiguous original two unambiguous versions; it really doesn’t take much in the way of extra cues to convince your brain.)
I found that briefly very disturbing—it seemed that the mere presence of an “L” or “R” on the vertical leg was sufficient to get my brain to see it one way or the other, even though I’d given no conscious thought to the question of which leg was which.
But of course it isn’t actually the choice of letter that makes the difference. (I haven’t said what is in case anyone else is in the same boat as me and wants to take a few seconds to work it out.)
Every frame that can be interpreted as her facing the observer and standing on her left foot can also be interpreted as her facing away from the observer and standing on her right foot.
That’s exactly what I thought as well.… except the other way around.
Freaky.
ETA: ok, I just looked at it again, for the first time in several hours, and now I see her on her left foot, and can’t make myself see her on her right foot (opposite of before).
This keeps getting freakier and freakier. I feel like my brain is defective.
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.
I’m having a hard time trying to figure out how to explain the phenomenon I just witnessed. I went back to that link feeling that I might have missed something and I’d give it another try. In the first image she is clearly spinning on her left foot, the same way I always see it. I then look at the second image. Same thing. On the third image, I thought I was seeing it the way I always do, but when I looked at which foot was on the ground, it was her right! Since the foot in the middle never moves except for up and down, I wondered how it could possibly be the same image. So I compared it to the one in the middle to see if it really was the same, and both rotate exactly the same! Every pixel is the same (except the ones with color.) How could this be possible! So I looked back at the first and compared it to the one in the middle. Same thing, every pixel where it should be, and her left foot was clearly the one moving up and down. How could this be! I thought about it and came up with the idea that if the backside was similar enough the the front, you could switch between which side you saw as front/back and left/right would chang accordingly. But this is not the case, they are far to different. I am completely dumbfounded to the physics behind this. Looking at it again, I can focus on the spot between the first and the second and watch them move the same, then switch to focusing on the spot between the second and third, making her suddenly stop and turn the other direction. By switching back and forth really fast, she quickly wobbles back and forth. I begging to wonder if magic is possible.
The backside isn’t just similar to the front, they are both exactly the same shade of black.
This might help you understand what’s going on: if you lie on the ground and have someone trace your outline, you can’t tell from the outline whether you were face up or face down.
Is there a pausible version of this? If I could freeze the individual frames, I might get it. I refuse to believe that her backside is that similiar, because just look at all the detail. Also, the part that reallly bugs me is not her direction of spin, but the fact I can’t even tell which way is right or left.
The detail is all in the outline (the part inside the outline is all black). From just the outline, you cannot tell
whether her foot is a little closer to you than it was a second ago or a little farther (so your brain picks one)
or whether she’s facing towards you or away from you (so your brain picks one).
The Wikipedia entry (link in OP) has a frame-by-frame version. (ETA: or you could download an animated GIF editor, and yourself produce from the ambiguous original two unambiguous versions; it really doesn’t take much in the way of extra cues to convince your brain.)
Also “versions of the image with an additional visual cue” (click “show”).
I found that briefly very disturbing—it seemed that the mere presence of an “L” or “R” on the vertical leg was sufficient to get my brain to see it one way or the other, even though I’d given no conscious thought to the question of which leg was which.
But of course it isn’t actually the choice of letter that makes the difference. (I haven’t said what is in case anyone else is in the same boat as me and wants to take a few seconds to work it out.)
Huh. I looked at each frame, and found that when she is facing the observer, she is clearly on her left foot. Weird.
Every frame that can be interpreted as her facing the observer and standing on her left foot can also be interpreted as her facing away from the observer and standing on her right foot.