Schizophrenic Brains Not Fooled by Optical Illusion | Hacker News Reader

Schizophrenic Brains Not Fooled by Optical Illusion

wired.com

85 pointslockem30 comments

I love the irony that sufferers of a disease "characterized by hallucinations, delusions", see the actual visual information while healthy viewers are utterly unable to see it.

And this: "Schizophrenia patients, meanwhile, may be unable to modulate this pathway, accepting the concave face as reality." is just too ironic, considering that the concave face is reality.

Maybe Schizophrenics are not the delusional ones.

This is really interesting. What more am I missing out from the "real" world?. If there wasn't an "authority" telling me that this face is concave I'll call anyone telling otherwise crazy.

this is exactly what I thought, too

I think we all labor under certain types of illusions on a daily basis - i.e. we ignore the dangers of driving because we have the illusion of control. If we thought about all of the permutations and repercussions of every action it might paralyze us. The mechanisms that we use to allow us to function day-to-day probably dull our senses.

The way I think about it: our brains create perception by combining raw observations with expectations derived from a mental model built on experience, in a process similar to a Kalman filter. Most of the time, the correction based on the mental model helps, such as when an object is partially obscured. Cases like the concave face are false positives for normal people, where experience overrides percpetion. Schizophrenics weight the observations more heavily than the predictions, so they are less likely to experience false positives, but I would expect them to be consequently more likely to experience false negatives (ie. perceiving things too literally, in spite of logic).

There are actually several diagnosable mental illnesses where the main feature or one of the main features is being able to see reality more accurately than other people. This is especially true with certain types of depression depression (e.g. depressive realism) and autism. My favorite though is delusional disorder, which basically just means that you're happier than other people think you should be given your circumstances.

"Schizophrenics aren’t the only ones who see the concave face — people who are drunk or high can also ‘beat’ the illusion."

I had a three beers watching the video, and the first revolution was a concave face. When the next revolution came I saw the illusion and now the illusion is so powerful I can't see it as concave face anymore. I hope that rules me out as schizofrenic...

Wait. Who wrote this.

Contrary to popular belief, schizophrenia is not the same thing as dissociative identity disorder/multiple personality disorder. (Which is I believe what you were suggesting with that joke.)

From Wikipedia:

    Schizophrenia is a mental disorder characterized by a disintegration of the 
    process of thinking and of emotional responsiveness. It most commonly
    manifests as auditory hallucinations, paranoid or bizarre delusions,
    or disorganized speech and thinking, and it is accompanied by significant
    social or occupational dysfunction.

http://en.wikipedia.org/wiki/Schizophrenia http://en.wikipedia.org/wiki/Multiple_Personality_Disorder

"dissociative identity disorder/multiple personality disorder" has been all but dropped by mainstream psychology. It's considered to be an artifact explained as being induced by a number of factors including attention seeking, desire to please therapist, extreme hypochondria and mimicry.

Whether or not it has been dropped by mainstream (source?) - you paint dissociative identity disorder in such a poor light - choosing only to focus on characteristics that make it controversial. I think you'll find that in fact there is simply a lack of consensis amongst psychologists for its basis - which happens to be the case for many 'disorders' in this arena.

As with many mental illnesses, whether or not it's real depends on what your definition of 'real' is. It's clearly a common pattern of behavior that's secondary to other factors, but you could say the same thing about lots of mental illnesses.

... back to the books for you.

I actually saw a concave face until I read the article. Now I see a regular face. I'm not drunk, high, or otherwise on any substance. I hope I'm not schizophrenic, though for some reason I've always thought that it would be awesome to have it like for a few days. So yeah. Concave faces.

Given the absence of a highly detailed model, in this case a Charlie Chaplain mask, the illusory effects may be due to the absence of sufficient visual depth cues - similar to the effects seen in the "Spinning Dancer" effect. As a further example, next time you see a plane in the air making a turn at a great distance from you, there are actually two ways you could perceive its direction - all dependant on what you convince your brain it to be first. I would not draw too many conclusions from such a vague study.

I agree. It's all dependent on what your brain sees first. It so happens that the absence of visual detail makes it easier to decide the mask as seen from the front instead of from the back. The moment your brain is told that it should not be seeing the concave face a switch turns on telling you how to 'see' the mask.

Am I the only one who has to always look up the definition (w/ example image) for concave and convex to differentiate them?

I always think that concave goes in, like a cave.

It's probably one of those things people end up memorizing, when learning about lenses or 3d figures like polyhedrons. It's like latitude and longitude. You can try to derive meaning from e.g. "lat = lateral", but then, do the lines go across or are they measuring distance across (which would make the lines vertical)? Either you memorize the correct answer, or you can easily get mixed up by over-analyzing the meaning.

concave -> (cave, cavity) -> hole

convex, you sort of just have to memorize. As best I can tell from introspection, I've associated the sound/visual of "vex" with "outward"

Vex, as in vertex. Bulging outwards. I think the proper way to remember those (I've struggled with them too) is actually use them a lot. For example, some mathematicians study convex geometry, which is a meaningful subject on its own.

*(lazy ninja edit)

I've been doing a lot of geo-related work lately and confounding latitude and longitude was a regular source of logic errors. Only useful for North America, but my mnemonic for lat/lng is "latitude has a positive attitude". It doesn't necessarily help when identifying which is which on a map, but when using them for calculating proximity or drawing polygons on a map it works every time.

The lines of longitude are always long, whereas the parallels of latitude can be shorter, and are always "parallel" (in some sense).

Newscientist also covered this. They have a couple more masks to look at http://www.newscientist.com/article/dn16911-schizophrenics-s...

Maybe the fact that I'm the only one mentioning this means I'm a little less intelligent than the rest of us, but...

Isn't a 'real' illusion one that causes you to see something that isn't objectively there? For example, The Grid illusion (http://en.wikipedia.org/wiki/Grid_illusion).

If you find an alternative way to create an identical image, then it's forgery, not an illusion.

Put another way, the Grid Illusion is to "worng sleplnig" what the Hollow Mask is to "conversation" (a word in both the English and French languages)

Did you watch the video?

Yes. Continuing the word based analogy, the video is just permutations of "conversation" leading up to it's correct spelling, then more permutations.

If you take the frame that show's the inside of the mask alone, is there a way to prove the image is of a concave object? To see it as convex is arguably 'wrong' but it's a moot point because you're looking at something that is objectively identical to a convex object anyway.

Couldn't I just extend your argument to say the fact that you see a face at the very start of the movie is an illusion? After all it's a mask, not an actual face.

err, i was able to switch it back and forth at will. however, my mind definitely kept wanting to visualize the concave face.

I remember reading and article/post/whatever a while back that said that some natives/tribes somewhere didn't see optical illusions. The implication was that it might be a product of more industrialized living.

( I may be confusing this a bit here. The first part may have been an article, and the second part may have been part of an HN discussion on it. )

There are certain (secluded) populations that do not report certain illusions (e.g., Muller-Lyer effect) as strongly as Western subjects do. Standard explanation is that, living in architecturally under-developed environments, they lack experience with corners, thereby diminishing corner-related illusions.

But that's not immunity, it's merely a highly interesting artifact. Goes to show that psychology's biggest problem might be excessive reliance on college students as test subjects.

I'll have to show this to my girlfriend later. She's been diagnosed as Schizophrenic, but has never agreed with that diagnosis.

I could only see it sticking out and couldn't change it back at all. My girlfriend, who's much more much more of an empath and more artistic, could switch it back and forth. Interesting...

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