Optical illusion no longer an illusion?

[Digger]

Forgot to give the source:

John R. Meyer

Department of Entomology

NC State University

General Entomology Tutorial Copyright 2006

http://www.cals.ncsu.edu/course/ent425/tutorial/photo.html

 

[MandellaMandy123]

I wonder if the eye was perhaps infected in some way which was causing the cells to move, therefore messing up the pseudopupil illusion? Just a thought - that would also explain the mantis' death. And the other eye looks black in the video. Was that the case? Because it could have been an infection that caused the eye to become black.

 

[Rick]

Again, the camera shake is too little compared to pupil erratic movement... I guess I'll have to wait for my next mantis death to convince you people

Thank you! Finally someone agrees with something!

The other pupil was not moving at all. That's why I never bothered filming it but i guess that was a mistake. If I had filmed both pupils at the same time, head movements and camera shake wouldn't even be discussed here. If these two situations were the culprits then both pupils should be moving but they weren't. Unfortunately I have no visual proof... Again.

It doesn't take much movement. I know what you think you see, I just don't agree.

 

[Orin]

That's such a funny video, I feel like I'm seeing a tall, dark, hairy shadow running through the woods in an overly grainy video.

 

[Orin]

... and a guy screaming "proof at last".

 

[Domanating]

I wonder if the eye was perhaps infected in some way which was causing the cells to move, therefore messing up the pseudopupil illusion? Just a thought - that would also explain the mantis' death. And the other eye looks black in the video. Was that the case? Because it could have been an infection that caused the eye to become black.

The left eye is not black. It is perfectly fine. I just had no light pointing to the left side of the mantis

... and a guy screaming "proof at last".

I wonder who did that.

Don't get me wrong but i would agree with everything you guys said, If only the left false pupil moved also.

 

[MandellaMandy123]

Oh, okay. Still I'm thinking it was moving cells in the eye or something. That would throw of the illusion of the pseudopupil. I do notice a lot of camera movement, just not correlating with the moments at which the pupil moves. I don't mean to be starting an argument here, but I do think something else was going on. A pseudopupil would move that much unless you were moving a lot....

 

[more_rayne]

It's head was moving as well as your camera. Even the slightest bit of movement will cause that illusion.

 

[Domanating]

I have reuploaded the video, this time with its original full length. In the last 23 seconds the pupil stopped moving so I removed that part. But now the additional 23 secs are there to show that the camera has nothing to do with the false pupil illusion.

I think I can predict some of the comments:

"The camera shakes less in the last 23 secs so the pupil doesn't move"

"The head stopped moving in the last 23 secs, so did the pupil"

WRONG! Nothing changed. And for the last time.... The head of the mantis does NOT move during the entire video except in 2 brief moments I mentioned in one of my previous posts.

 

[Rick]

The camera and the mantids mouth (head) is moving pretty much during the entire video. In order to rule those out as a factor you have to have zero movement from both. I do agree some of the pseudopupil movement is extreme compared to the camera and head movements, but you can't ignore the movements of both camera and mantis. However, I did see one extreme movement of the pseudopupil during a fairly large movement of the camera.

 

[Domanating]

The camera and the mantids mouth (head) is moving pretty much during the entire video. In order to rule those out as a factor you have to have zero movement from both. I do agree some of the pseudopupil movement is extreme compared to the camera and head movements, but you can't ignore the movements of both camera and mantis. However, I did see one extreme movement of the pseudopupil during a fairly large movement of the camera.

The mouth is not the head. If you refer to head movements the mantis needs to move the neck. If the camera shake is a factor can you explain the lack of movement of the pupil at the end of the video then? I breed mantids for more than 15 years and I know very well how the pseudopupil illusion "behaves". I am no amateur. This is something I've never ever seen before and believe me, I had a hard time convincing myself that the black dot was moving all by itself. That's why i picked the camera and that's why I posted it here.

 

[Rick]

The mouth is not the head. If you refer to head movements the mantis needs to move the neck. If the camera shake is a factor can you explain the lack of movement of the pupil at the end of the video then? I breed mantids for more than 15 years and I know very well how the pseudopupil illusion "behaves". I am no amateur. This is something I've never ever seen before and believe me, I had a hard time convincing myself that the black dot was moving all by itself. That's why i picked the camera and that's why I posted it here.

During much of the mouth movements the head is moving as well. I can clearly see it. I don't know what else to tell you other than your camera is moving and since you have so much experience you should know that as the observer moves the pseudopupil moves as well. There is no "if" on the camera movement being a factor here. We explained earlier what the pseudopupil is and how it's observed.

 

[Domanating]

During much of the mouth movements the head is moving as well. I can clearly see it. I don't know what else to tell you other than your camera is moving and since you have so much experience you should know that as the observer moves the pseudopupil moves as well. There is no "if" on the camera movement being a factor here. We explained earlier what the pseudopupil is and how it's observed.

I hope you you're seeing the wrong video because I see the head perfectly stationary.

And I explained as well that the observer needs to move a lot to make that pupil move that much.

I even tried recreating this situation under same light and angle as in the video with my females and the pupils didn't even move. Plus as I explained previously, I had my head stationary when I witnessed this, the right pupil was moving but the right wasn't. How many times must i say this?

Also you evaded my question there. Ok, lets forget the "if". How do you explain that the pupil stopped moving in the last 23 seconds of the video with all the camera shakes and your imaginary mantis head movements?

I may be stubborn m8, but for a good reason. I would have witnessed this a million times, if it was common. Your critics and skepticism made me pay closer attention to the pseudopupil for the last weeks and I could not recreate what I filmed, Not with my females nor with another male that died some days later. If the illusion is so common as we all know, why can't I recreate it like in the video? That's another question I would like answered.

 

[Rick]

Your critics and skepticism made me pay closer attention to the pseudopupil for the last weeks and I could not recreate what I filmed

Which is exactly why I am offering up the criticism. It isn't to be hateful or anything as it may come across in text. It is to get you to look at the variables for an explanation possibly.

The head is moving during some of the video. Surely I am not the only one seeing that. The mantids mouth is moving a lot which in my experience will move the entire head to some degree. There is no doubt we have lots of camera shake. I agreed with you in an earlier post that some of the pseudopupil movement is extreme compared to the camera movements.

During many of the large pseudopupil movements the mantis raises itself slightly off the substrate right after you see the dot move.

 

[Domanating]

Which is exactly why I am offering up the criticism. It isn't to be hateful or anything as it may come across in text. It is to get you to look at the variables for an explanation possibly.

I'm aware of that. I just can't believe that the camera shake and the mantis head movements (which i still can't see, besides 2 small spasms i mentioned earlier, but moving on) make all the factors for the pupil moving that much. As you said, you seem to agree with me at some point, since some movements are way off normal.

What's more suspicious is I can't make that happen again.

 

[Rick]

I'm aware of that. I just can't believe that the camera shake and the mantis head movements (which i still can't see, besides 2 small spasms i mentioned earlier, but moving on) make all the factors for the pupil moving that much. As you said, you seem to agree with me at some point, since some movements are way off normal.

What's more suspicious is I can't make that happen again.

I do agree with you on that, but you cannot dismiss the camera moving. I want to think that it has something to do with the camera and how it processes the image, but you said you saw it with your naked eye too. But not being able to recreate it has me wondering if it was just an illusion of sorts.

 

[Domanating]

Well, I think this will remain a bit of a mystery until some better quality footage comes up. So far I can only say that this happens when the mantis is dying I guess? In between the common spasms before death.

I will keep track of this with the following mantis deaths and hope I can somehow recreate this weird situation. I will try both to film in a stationary position and with a shaky camera.

I have only 2 females left. If i miss their dying process, I'll have to wait until next year or probably 2 or 3, who knows.