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Weird optical illusion involving faces

Fast Eddie B said:
Not sure what you’re getting at. Of course a sequence of photos is presented sequentially. Sounds tautological.

The illusion depends on the photos flashing by rapidly.
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Maybe what I'm saying is too obvious to be even worth saying: All I'm saying is there is a merging/contrast/morphing kind of thing going on in the sequential presentation of faces, what with persistence of vision and all that, that causes the illusion. For example, my hypothesis is that if you present a sequence of faces that are similar to each other the effect just might disappear. It's only when the sequential faces contrast in a certain way (that I can't begin to rigorously define) that the illusion occurs.

That's my guess, anyway; I could very well be wrong.
 
Cabbage said:
For example, my hypothesis is that if you present a sequence of faces that are similar to each other the effect just might disappear. It's only when the sequential faces contrast in a certain way (that I can't begin to rigorously define) that the illusion occurs.
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Sure. Nearly identical - or identical - faces would not elicit the illusion.

The researchers said as much. Our brains just amplify what appear to be deviations from the norm. A high forehead or large eyes become grotesquely high or large.

Cool illusion, whatever the underlying cause.
 
Cabbage said:
Maybe what I'm saying is too obvious to be even worth saying: All I'm saying is there is a merging/contrast/morphing kind of thing going on in the sequential presentation of faces, what with persistence of vision and all that, that causes the illusion. For example, my hypothesis is that if you present a sequence of faces that are similar to each other the effect just might disappear. It's only when the sequential faces contrast in a certain way (that I can't begin to rigorously define) that the illusion occurs.

That's my guess, anyway; I could very well be wrong.
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The necessity is that the faces are in your peripheral vision and that the eyes are precisely aligned with each other. The creators of the illusion painstakingly aligned the eyes.
 
Fast Eddie B said:
Sure. Nearly identical - or identical - faces would not elicit the illusion.

The researchers said as much. Our brains just amplify what appear to be deviations from the norm. A high forehead or large eyes become grotesquely high or large.

Cool illusion, whatever the underlying cause.
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All of the faces are normal. So then what does "deviation from the norm" even mean?
 
Fast Eddie B said:
If you’re talking about the illusion in the OP, the gaps come from insufficient time to process the images, not gaps in the images themselves.
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You seem to be suggesting something that we can't yet establish. You seem to be suggesting that if the video was slowed down or paused between face changes then the illusion would not occur.

There must be some ISF member with the technical ability to create a slow-motion version of this video. Can anyone do that and post it?
 
p0lka said:
In my example with the mirror when it's dark, it's dark so your face isn't clear.

In the example in the OP, you are seeing the face/faces in your peripheral vision, so again the face isn't clear.
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When your subconscious creates a double-sized forehead it doesn't seem to be filling in anything unclear. Doubling the size of a mouth (while not changing the size of other features) doesn't seem to make the face "clear" at all.

What is the subconscious accomplishing when it creates monstrosities instead of actual clarity? The "substituted" bits offer no clarity at all. The giant forehead is just as blurry as the normal forehead that it replaced.
 
William Parcher said:
You seem to be suggesting something that we can't yet establish. You seem to be suggesting that if the video was slowed down or paused between face changes then the illusion would not occur.

There must be some ISF member with the technical ability to create a slow-motion version of this video. Can anyone do that and post it?
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That should be easy to do, albeit in a rough manner using an iPhone, computer monitor an iMovie, unless I can find a way to download the original file.

I'll get back to you on that.

I think its certain the effect will diminish and then eventually disappear as the speed decreases.
 
Fast Eddie B said:
Well, at 1/4 speed I still see the effect and it lingers for quite some time:

https://youtu.be/ZvFd0--o_XM

I'm surprised at that result - I thought the speed was more of a factor than it apparently is.
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I paused the original video and can still see the odd effects (even when using one eye and/or covering one of the faces) as long as I focus on the cross. The effects aren't as strong with the video paused, but still are there.
 
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Cabbage said:
Actually, my hypothesis would be that it IS merging two faces, just not the side by side faces. I think it's merging the sequential faces instead (or contrasting them in some way).
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Makes sense.

Test it by covering one eye.

I tried it. One eye, one image and the effect remains.
 
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