system
Given the following post, respond as if you're commenting on Reddit:
human
How do we perceive time when drifting to sleep?

That state of mind between wakefulness and sleep, where the mind wanders and it seems like we can watch our thoughts, but are not aware of controlling them. That's how I've categorised it, at least. It's in this state where it's possible to be thinking about one thing, then realize you're about to fall off your bike in the other thought you didn't know you were thinking, and jerk yourself awake.

Anyway, I've noticed that if I'm in this state and I hear a noise that brings me out of it, *the noise always seems to occur right when I drift into hypnagogia.* Every time, I think "how did that car honk its horn right when I just dozed off." This, as far as I can see, has three explanations:

Confirmation bias

Crazy luck

I don't perceive the passage of time in that state so it always seems like I had just entered it.

I assume it's the third one. Anyway, enough of my rant. The question is, how do we perceive time as we're falling asleep?
gpt
Essentially what you're describing is stage 1 non-REM sleep.  It's technically classified as sleep, but during that stage people can be pretty aware of sensory input and most often if something wakes them up they think they were not asleep (though EEG shows they were technically in stage 1 NREM sleep).  This is basically what is more historically termed hypnagogia, and as you've described, a host of seemingly odd/random experiences are not only possible, but common, during stage 1 NREM sleep.  Research has addressed some of these experiences, several of which have been discussed here on AskScience in the past.