ELi5 How does hallucinations work?


So I was thinking about how hallucination work exactly.

Us humans can see stuff when the light reflected from the object is “absorbed” by our retina, but if hallucination are made up in your mind and are not actually real, how can we see them?

There may be a simple answer but I’m not the brightest dude out there lol

In: 3

The easier way to describe this is imagining:

– your eyes/ears
– your brain (just like the organ)
– your mind (your conscience)

As 3 guys playing the telephone game, but with pictures

In a normal situation:

– the eyes/ears take a photo
– the brain draw what the eyes photographed
– the mind look at drawing

When you allucinate the middle step is not working properly. So the eyes pass the right signals to the brain, but the brain isn’t able to put it together in the right way so it makes you see or ear the wrong things.

This because your brain have the task to bring signals from other organs, decipher then and out them together in a big understandable picture.

That’s why people play games like amnesia in a dark room and with headsets.

Dark room+dark game= your mind it’s tricked into merging the screen with the real world.

Headset: you are isolated from real world sounds and can rely just on what the game gives you.

Your eyes are just sensors. They record a very limited spectrum of light.

Your brain processes that signal. And your brain does a lot of filtering and extrapolation while it does this. For example, your brain helps you be unaware of a lot of unnecessary details. That’s why you’re not constantly aware of your nose in the middle of your field of vision. Or meaningless details like how many bricks there are in a wall (unless you focus on it).

Your brain also helps fill in the blind spots in your field of vision. You’re blind when you move your eyes for example but you don’t really notice this because your brain helps you out.

And your brain prefers focussing on some things over others. Threats, moving objects, the faces and expressions of other people and so on.

So your eyes are just the sensors. Your brain is what decides what you actually see. This also means that your brain can make you hallucinate things that aren’t really there.

For example, if you put some white domes over your eyes, your brain gets zero visual input. This feels like an impossibility to your brain so it’ll try to translate nothing into visual stimuli and you can start to see mild hallucinations.