Interesting, but pure speculation.

I would add an additional fact which seems to be contrary to the proposed model: I regularly wake up a few minutes before my alarm clock, in plenty of time to turn it off.

I believe I have a fairly good sense of time (but have no empirical evidence for that!)

This is what I was thinking the whole time I was reading. The author and I must be talking about two different things. Because when I say I woke up just before the alarm, I mean enough time to turn it off before it goes off. But within 5 minutes.

This is just your subconscious mind at work.

I read this back in jr high and still one of my goto techniques when trying to solve a problem.

This book: http://www.amazon.com/The-Power-Your-Subconscious-Mind/dp/16... Some spiritual stuff in it, but if you're not into that, read it for the way your brain/subconscious works. great read and in fact one of the examples in there is telling yourself you NEED to wake up at a certain time and then waking up right at that moment.

I wake up about 5 minutes before I wish to wake up. After doing this a few months I stopped setting the alarm and continued to wake up on time.

I think it is likely related to training against other criteria: birds, sunrise, cars ... etc. since a change in location will throw off my timing and require a few weeks to learn the new 'time'.

Zen alarm clocks are awesome btw, http://www.now-zen.com/. I love mine and used it extensively when I was a student. The alarm is sounds beautiful and seems to week. The association of a particular bell sound with the requirement of waking is powerful. After using the alarm for a few weeks I no longer would remember hearing it but feel compelled to get up and disable the alarm before it could ring again!

When I'm going to sleep at reasonable time I wake up within 5 minutes of 06:00 no matter if I set the alarm or not.

When I'm not having enough sleep I wake up after alarm goes off, and usually it's already beeping for a few good minutes, before it wakes me. And I do notice immediately that it's after the alarm.

So I doubt waking before alarm is an ilussion.

It is already well understood that our brains can keep track of time. I think the author is mistaken with their Occam's Razor assertion.

Alarm clocks often turn on the speaker, making audible noise in doing so, slightly before sounding the alarm.

It bugs me too and it happens quite often! Always within the minute! Internal time keeper?