system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 What's happening in my head when sound gets drowned out while falling asleep and then a minor disturbance "opens" up my ears?
gpt
Your brain differentiates between expected and unexpected noises. So the hum from the fridge or the music you left on is expected, but broken glass or some other noise is unexpected and your brain wakes you up.