no but seriously I still get chills thinking about turning off my headlamp in the cave and The Hand That I Did Not Actually See, and it’s been twelve years since it happened
it’s such an unreal experience
like
you turn off your light in a cave and wave your hand in front of your face
and
you can see this shadowy thing moving in the black space where your hand is
it looks like the same shadowy thing you would see in your room at night if you waved your hand in front of your face, it’s there and vaguely hand-shaped, and your brain recognizes it as your hand because your brain is aware of where your hand is and what it is doing
But You Are Not Seeing Anything
Inside a cave, there is No Light. No matter how far your pupils spread, there is no light for them to draw in, no light to put an image on your retina.
But your brain just Fucking Assumes that because it knows where your hand is and what it is doing, clearly it can see it.
So it creates a shadowy thing for your eyes to be seeing.
Brain is like “there’s a hand there”
Eyes are like “yup sure thing brain I can totally see it”
Brain is like “nice”
but there is no hand, you cannot see the hand, you are seeing a literal actual hallucination in the cave because your brain thinks it knows best
Caves are awesome, but also terrifying. Thank you for coming to my TED Talk.
we once went spelunking, and a our guide said that once he was in a cave with a stream, so he could hear running water, and his brain was like ‘oh, running water? that means there must be Ducks out there’. and he saw like…low light shadows of ducks. that his brain just Put There.
As a cave guide: we call that ‘cave blindness’! True darkness absolutely wigs your brain out - we’re such visual creatures that after a while our brain throws a hissy after not seeing anything. Sensory deprivation is a very real kind of torture. We have a huge, deep cave system at work and there are a lot of places where you’re hundreds of meters in solid rock in this tiny, dark, still space.
I like to turn my torch off, sit down with my back against the wall, and wait to see how long it takes before I start seeing things or feeling like the ground is moving, or hearing things. Because I know I’m not - I’m in complete darkness, utter silence, sitting in rock that hasn’t moved in hundreds, if not thousands, of years.
Proof that brains are Ridiculous and over-react to a lot of stuff!
During the most recent caving trip I went on, our little group took a break in a large chamber to sit down and turn off our head lamps and wait in silence until we started hallucinating. It only took a few minutes for most of us to start "seeing" lights, shadows, or one another. I like to imagine this was a pastime for paleolithic people as well.
