Speaker 1: Welcome to Stuff to Blow Your Mind, a production of
Speaker 1: iHeart Radio. Hi, my name is Joe McCormick, and this
Speaker 1: is the Artifact, a short form series from Stuff to
Speaker 1: Blow Your Mind, focusing on particular objects, ideas, and moments
Speaker 1: in time. It's well known that visual hallucinations can be
Speaker 1: induced by psychedelic compounds like LSD, d MT, mescaline, and psilocybin.
Speaker 1: But according to a now copious body of research, there's
Speaker 1: a fairly reliable and less chemically exotic way to make
Speaker 1: people with otherwise typical vision see things that aren't there
Speaker 1: deprive the eyes of light and weight. One example. In
Speaker 1: two thousand four, a study was published in the Journal
Speaker 1: of neuro Optomology by Lotvie Marabet, Denise McGuire, Aisling Ward,
Speaker 1: Karen Alterescu, Robert Stickle, and Alvaro pascual leone called visual
Speaker 1: hallucinations during prolonged blindfolding insided subjects. This study actually took
Speaker 1: place within the bounds of a larger study about learning
Speaker 1: and brain plasticity under sensory deprivation. A couple of the
Speaker 1: test groups of that larger study required subjects to wear
Speaker 1: a blindfold for ninety six hours straight. Now, this wasn't
Speaker 1: just a strip of cloth tied around the eyes. It
Speaker 1: was a sort of power blindfold that prevented any light
Speaker 1: perception whatsoever. Quote It was held in place by a
Speaker 1: velcro strap and further secured by ace bandages. The blindfold
Speaker 1: permitted full motion of the eyes, as well as opening
Speaker 1: and closing of eyelids. Potential tampering with the blindfold by
Speaker 1: the subjects was controlled with the use of a piece
Speaker 1: of photographic paper attached to the inside of the blindfold.
Speaker 1: All subjects were issued a handheld microcassette recorder with automatic
Speaker 1: date times stamping, and directed to report their thoughts, feelings,
Speaker 1: and perceptions related to the experiment throughout the day as
Speaker 1: frequently as they desired. Now, what was so interesting about
Speaker 1: these micro cassette diaries is that, without prompting, out of
Speaker 1: thirteen subjects total, ten reported experiencing visual hallucinations on average
Speaker 1: after about a day of blindfolding. These visions varied a lot,
Speaker 1: from simple perceptions of flashing lights known as phosphenes, to
Speaker 1: complex imagery like people, environments, and ornate objects. Subject four,
Speaker 1: a twenty three year old man, reported seeing a strange
Speaker 1: assortment of vivid geometrical shapes, warping jigsaw puzzle pieces, a
Speaker 1: triangle with bold dots at each vertex, and quote a
Speaker 1: large X with a light shining underneath it. Subject eight,
Speaker 1: a twenty year old woman saw cities, skies, kaleidoscopes, lions,
Speaker 1: and a butterfly that became a sunset. Quote if there
Speaker 1: is a sunset or a sunrise, I couldn't look at
Speaker 1: the sun because it was too bright. It would seem
Speaker 1: like all of this light would just collect where the
Speaker 1: sun was, and I just could not look there. Subject six,
Speaker 1: a thirty four year old man reported intricate visual hallucinations
Speaker 1: while listening to music, particularly Mozart. First he saw skulls
Speaker 1: and ceremonial masks, then the image of an old woman
Speaker 1: sitting in an airplane seat whose face transformed into the
Speaker 1: face of a rodent. Subject to A twenty four year
Speaker 1: old man saw all kinds of imagery, flashing lights, lamps, trees,
Speaker 1: mirrors and full landscapes, ornate buildings of green, white marble,
Speaker 1: and cartoon figures, but he also perceived obstacles in his
Speaker 1: path while walking from place to place, believing while walking
Speaker 1: outside that he saw ditches in the dirt stones and
Speaker 1: streams of water. One interesting variation was that some of
Speaker 1: the hallucinations were context appropriate. Subject one, a twenty nine
Speaker 1: year old woman, experienced one hallucination twelve hours after the
Speaker 1: blindfolding began. She stood in front of a mirror which
Speaker 1: she knew was there, but of course couldn't see, and
Speaker 1: suddenly a face appeared where her reflection should have been.
Speaker 1: Only it wasn't her face, but quote a green face
Speaker 1: with big eyes. Subject three, a twenty four year old woman,
Speaker 1: had been napping when her sister arrived to visit. As
Speaker 1: her sister entered the room, the subjects saw quote a
Speaker 1: splotch of light in the exact form of Elvis Presley.
Speaker 1: In both of these cases, the brain saw a human
Speaker 1: figure where it knew by a combination of memory and
Speaker 1: other senses that one could be found, only it didn't
Speaker 1: see the correct human figure. But other visions of this
Speaker 1: kind were more accurate. Subject five, a twenty nine year
Speaker 1: old woman, reported, on the second day, quote, I have
Speaker 1: the sensation and that I can see my hands in
Speaker 1: my arms moving when I moved them, and leaving an
Speaker 1: illuminated trail when she reached out to pick up an object.
Speaker 1: She realized she could see her hands doing what they
Speaker 1: were doing, even though there was no light reaching her eyes.
Speaker 1: Subject ten, a twenty one year old woman, experienced something
Speaker 1: similar as she was eating a meal. She reached out
Speaker 1: to a water pitcher to pour herself a drink and
Speaker 1: suddenly reported that she could see what she was doing. Quote,
Speaker 1: I felt like I was seeing the pitcher while I
Speaker 1: was pouring the water. These last variations about context dependent
Speaker 1: hallucinations were the most interesting part of the study to me,
Speaker 1: since they might cause us to question what we mean
Speaker 1: when we distinguish hallucination from real sight. The fact that
Speaker 1: our eyes receive no light might not mean that we
Speaker 1: can't see. This type of lightless vision of one's own
Speaker 1: body has been observed in other contexts. Just one example,
Speaker 1: spelunk is in the total darkness of a deep cave
Speaker 1: sometimes report that they can see their own hands and
Speaker 1: arms and the movements of their own body. This is
Speaker 1: sometimes known as the spelunkers illusion. The eyes sense light,
Speaker 1: but seeing happens in the brain, and it turns out
Speaker 1: the visual cortex can not only mistakenly see things that
Speaker 1: aren't actually present in the case of a hallucination, it
Speaker 1: can also see things that are present accurately when the
Speaker 1: brain is informed of them by sources other than light,
Speaker 1: such as hearing, touch, appropriate reception, and memory, which is
Speaker 1: in fact consistent with lots of research showing that people
Speaker 1: with permanent blindness often recruit the visual cortex of the
Speaker 1: brain to do things like make mental maps of environments,
Speaker 1: even though those maps are not based on light perceived
Speaker 1: through the eyes. So what does it mean to see?
Speaker 1: Tune into new editions of the artifact each week, hosted
Speaker 1: by the Robert or myself as always, You can email
Speaker 1: us at contact at stuff to Blow your Mind dot com.
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