I don't understand quite how the sleep thing works if you sleep with a cat. How does it know that it is me and not the cat moving around.

I think the sensors are ones you wear on your person, like the FitBit that's a bracelet, or a sensor you clip to your clothes.

this whole hallucinations thing makes me understand where alien sightings/abductions come from.

damn y'all.

brains scare me.

When my older brother was around three or four, he'd see wolves outside the window while he was in bed. And sometimes he'd see our cousins come in his bedroom, except their heads were not attached to their necks--the heads were floating an inch above the necks, leaving a gap.

I used to semi-frequently (mostly only in hotel rooms but I'm in those more often than most) dream someone had come Into my room, and I'd wake up and swear I felt someone get into bed with me, feel the weight as they settled in, etc, and I would be frozen, unable to move but knowing something awful was going to happen...and them I'd fully wake up and still be freaked out but be able to move and know there was no one there.

Oh oh oh! One of my students wrote about this phenomenon. It is, as the anecdata her suggests, fairly common and usually associated with disrupted sleep. If it happens frequently it might be an indication of an underlying sleep disorder. It's also a likely source for beleif in things like alien abduction and demons like the succubus.

Like, do they drop resolution with reality?

I vote no. One of my recurring anxiety dreams growing up involved blurred vision and being unable to see clearly. I stopped having that dream in my late teens, and it didn't come back after I started needing glasses. I don't recall any dreams where I perceived myself to be wearing glasses.

YDMV

I still have Netflix DVD service too. But I keep a DVD forever.

Me too for both.

The similarities among stories of hauntings and alien abductions tells me there's a part of the human brain that creates these "stories" and sensations, but why?

If you don't know the scientific explanation for what you are seeing and feeling, haunting and alien abduction are fairly convincing.

When I was a kid I had the hypnopompic kind all the time, especially if I woke up needing to pee. This meant that late night trudges to the bathroom required wading through shark infested waters or darting past skeleton arms that reached out from the walls.

Wow, I'm not going to complain about the cat waking me up 15 minutes before the alarm any more. I normally get very good sleep--once I actually go to bed. Hubby was always jealous of the way I can drop off. Those hallucinations would drive you away from sleep.

And then there's Mike Birbiglia, who ran out of a hotel room window. [link]

I've only had the hallucination thing once that I remember, but it was fucking terrifying, especially since it repeated. I would wake up a little, be convinced that someone was moving in the room nearby, fall back asleep, wake up, see the person again, and I couldn't move.