system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does time slow down when you're about to be in a car accident?
gpt
Under normal conditions, your brain effectively discards large amounts of sensory information - input from your eyes, ears etc. - because it's just not useful. When you're in danger, particularly something extreme like a car crash, less of this information is thrown away and you start forming short-term memories at a drastically increased rate. This helps you become more acutely aware of your surroundings and better able to protect yourself, because you're processing more of the input given to you by your senses.

After the fact, when you remember the traumatic event, it seems like it took far longer than it actually did - it feels like time slowed down during the event. This is because you have far more memory of it than you normally would - the memories aren't necessarily more *vivid* (though they may be), but you have more of them.

It's entirely an illusion, of course, but a very compelling one.