system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: The phantom text, how does the brain feel something that isn’t happening? what causes this sensation? And are there other known symptoms of this phenomena?

Surely you’ve experienced it, you feel your pocket buzz, as if you had received a text message, only to find your phone is not even in your pocket that moment. What causes this sensation? Whatever this phenomena is, are there other examples of it? 

Sometimes we feel like we are still wearing glasses when they are taken off, how does the brain feel something that doesnt exist? 

Thank you for any answers!
gpt
Your brain has to process a *lot* of sensory input all at once. Way too much for you ever to really handle on a conscious level. To compensate for this, your brain learns to look for patterns in the raw information and then slots new sensory information into those patterns whenever it thinks it fits.

This is why you can, for example, recognize that a chair is a chair without having to take a detailed account of how many legs it has, or check to see if it has a seat or a back or any of the other things associated with chairs. Your brain gets the raw feed, identifies a shape that looks like a chair, tags it as a chair and then passes that up to you with the note “This is a chair, no need to waste time thinking about it too much unless you decide you need a chair.”

On the flip side, if you’re doing something like Where’s Waldo. There’s a lot of chaotic information meant to obscure the relevant patterns that would allow your brain to quickly process “Yep, that’s Waldo” even when you are looking directly at him. But then once you have looked closely enough for that connection to be made, your brain keeps track and you can’t *not* see where he is even though you couldn’t a second before when looking at the exact same picture.

Sometimes, though, a bit of sensory input is just close enough to an existing pattern that your brain misclassifies it, and so instead of passing along something approximating the raw feed so you can figure out what it is for yourself, your brain says “I know what that is!” and passes along the tag for “buzzing cell phone” or “your name shouted from far away” and so that’s what you experience instead of whatever it was that actually happened, which may have been *kind* of like that thing, but not really as much as you experienced it as.