Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Medical Pareidolia Hallucinations?

  1. May 20, 2010 #1
    Recently, I stayed up without any sleep for around 48 hours. I realized I needed to finally get to sleep because in my peripheral vision it looked like I could see someone facing away from me, then he would turn to look at me, and as soon as I turned to look at "him" it would just be a shelf full of things. It was like I started to see even the vaguest of pareidolia in things. Is this the same thing as a hallucination? I've never had hallucinations before this point, so I was curious if this is considered a hallucination? Obviously I knew I was just seeing things, but I would see it several times, the same "pareidolia hallucination" before I finally just said "I've gotta go to bed".
  2. jcsd
  3. May 21, 2010 #2


    User Avatar

    Staff: Mentor

    Lack of sleep can cause hallucinations or in your case misinterpreting what you see.
  4. May 22, 2010 #3
    I looked up "Pareidolia" on the wiki and also in the skeptic's dictionary. The skeptic's dictionary explanation completely misses the point, but the wiki definition gets it:

    "Pareidolia is a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant."

    The inportant part is "being perceived as significant".


    The skeptic's dictionary wrongly implies the error is in perceiving the image in the first place:

    "Pareidolia is a type of illusion or misperception involving a vague or obscure stimulus being perceived as something clear and distinct."

    http://www.skepdic.com/pareidol.html" [Broken]

    On the skeptic's page they show a piece of toast with what is obviously a chiaroscuro rendering of a young man's face on it. They are wrong to imply there is an error made in seeing that face. It's about the same amount of visual information you might be given about a face in some realistic paintings where it's intended to be seen through mist, or smoke, or in the background in dim lighting. The error, the pareidolia, would be in interpreting the presence of that face on the toast as a "miracle", or a paranormal occurrence.

    So, I think what you experienced was not pareidolia. Your assessment of your experience, that it was essentially not real, and caused by sleep deprivation, demonstrates you weren't putting a "bizarre" interpretation on it.

    That said, I'm inclined to say the best term for it might be "mild hallucination", based on the fact you saw it move: it "turned to face you", which stuff on a bookshelf wouldn't do, even if it looked like a face in your peripheral vision. The fact it disappeared when you tried to look directly at it is what makes me characterize it as "mild".

    On the other hand if the sense of it moving were caused by something purely optical, like your eyes watering, then I'd call the whole thing an "illusion".
    Last edited by a moderator: May 4, 2017
  5. May 23, 2010 #4
    It is tough to call, but I would agree with Evo. Sleep deprivation TENDS to result in a predictable series of hallucinations, and the first is the sense of something moving in your peripheral vision. Some have dubbed these, "brown furries" in a fit of whimsy, because they often appear as indistinct black-brown objects (the peripheral vision is primarily gray-scale).

    After that, seeing transient colors, and working into the classic psychotic hallucinations of insects, usually the SENSATION of ants on the skin or the like, follows. 48 hours without sleep however, and you'll be seeing patterns in everything, which your deprived brain tries to make sense of. Misinterpretation, and a slowed cognition to regulate that make the most sense here.
  6. May 24, 2010 #5
    Appreciate the help guys. I wish I could give more detail, but it was about two months ago, so I don't vividly remember it. Maybe I should stay up again to continue the experiment, hoho.
  7. May 24, 2010 #6
    But that was originally probably caused by sleep and lack of focus. Now you'll be focused on it. :tongue:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook