Besides the overlooked possibility that people are just better at waking up at specific times than is generally expected (which I think is true and probably explains most cases, but maybe not all), there's another explanation the author didn't consider: it's possible that people frequently half-wake-up, and then fall back asleep and forget the experience. However, if you half-wake-up right before the alarm, then the alarm interrupts you before you get the chance to fall back asleep and forget the experience. You just think that you unusually woke up right before the alarm, without remembering the many other times you woke up in the morning not immediately before the alarm.
I used to have an alarm clock very close to my bed, and I would be able to turn it off or hit the snooze button very quickly after it went off without getting up. I believe I could hit the button in my sleep, or wake up just enough to hit it and then fall back asleep fast enough to forget the experience. I remember many times waking up at my alarm starting to go off at 9:30am (or some other round ten minute interval time after 9am) even though I scheduled it at 9am; I must have snoozed it several times and fell back to sleep quickly enough to forget the experience.
I even switched to a phone alarm clock app where I had to solve simple arithmetic problems in order to snooze or disable the alarm, and I had the same experience. I'm not sure it if it makes sense to say that I was solving the math problems in my sleep; I think it's more correct to say I woke up, solved it, and then fell back asleep and forgot the experience because I fell asleep quickly enough.
> I believe I could hit the button in my sleep, or wake up just enough to hit it and then fall back asleep fast enough to forget the experience. I remember many times waking up at my alarm starting to go off at 9:30am (or some other round ten minute interval time after 9am) even though I scheduled it at 9am; I must have snoozed it several times and fell back to sleep quickly enough to forget the experience.
That happened to me quite a lot during college, and due to a quirk of my alarm I know for certain I wasn't just sleeping through it: The snooze button was between the two arrow buttons for setting stuff, and if I hit an arrow by accident while the alarm was going off, the set alarm time would change. It pretty regularly ended up several minutes off of where it was supposed to be.
I used to have an alarm clock very close to my bed, and I would be able to turn it off or hit the snooze button very quickly after it went off without getting up. I believe I could hit the button in my sleep, or wake up just enough to hit it and then fall back asleep fast enough to forget the experience. I remember many times waking up at my alarm starting to go off at 9:30am (or some other round ten minute interval time after 9am) even though I scheduled it at 9am; I must have snoozed it several times and fell back to sleep quickly enough to forget the experience.
I even switched to a phone alarm clock app where I had to solve simple arithmetic problems in order to snooze or disable the alarm, and I had the same experience. I'm not sure it if it makes sense to say that I was solving the math problems in my sleep; I think it's more correct to say I woke up, solved it, and then fell back asleep and forgot the experience because I fell asleep quickly enough.