When I wake up from a sleep, I have a sense of time having passed since I fell asleep. It’s not always accurate, but is more often than not. However, when I recently went under general anaesthetic, the effect was more like having closed my eyes in the operating theater, and opened them in the recovery room.
Is this effect merely one of expectation, or is there some kind of subconscious clock measuring the passage of time while asleep, which gets knocked out by general anaesthesia? Do people in coma experience time?
I think you may be fairly unusual in having a sense of time having passed while asleep; the only way I get a clue as to how long I’ve slept would either be daylight or a clock (or maybe my stomach). I thought I was ‘normal’.
The body does have certain time-critical processes that we use to measure the passage of time. There was a very good article in the September Scientific American on this topic (Times of Our Lives by Karen Wright). Unfortunately the article is available online only for a fee. (I have the hard copy at home.)
It didn’t specifically address this sense while asleep vs. anesthetized vs. other states. I would venture a guess that certain drugs interfere with these processes. I had a procedure that required a sedative, not even a general anesthetic. Even though I was conscious the whole time my memory of the event was never recorded, and my sense of time was all messed up. So it wouldn’t surprise me if the same thing that interferes with memory could also interfere with the sense of passing of time. This could true for many unnaturally altered states of consciousness. People taking recreational drugs remark on an altered sense of time.
I think it has more to do with dreaming. Under general anesthesia (and sometimes if you smoke pot prior to going to bed) you don’t dream. Dreams act as reference points throughout the night by which your mind can gauge the passing of time. But if you don’t dream, there’s nothing to reference, so you get that sense of the night passing in a blink.
I’m not a doctor (nor do I play one on TV), but that just seems to me to be the reason.
Peoples perception of time can also be reliant on external modes of reference: I remember reading of a psychology experience in which two groups of people were left to wait in a bare room with only a clock on the wall, and secretly observed. One room had a clock running at 2/3 pace of a normal clock, the other at 4/3 pace.
The people in the rooms reacted very differently according to their perception of passing time: the ones in the ‘fast clock’ room got hungry sooner, more tired etc… their ‘body clock’ fell into line with the perceived passing of time from the fake clock on the wall.
On the OP, I also have an innate, immediate sense of how long I have been asleep (even if only a nap), but this, obviously, whilst not entirely reliable, is a good indicator of some kind of bodily time-keeping awareness. I think it is quite usual, although if I wake unexpectedly in the night in a darkened room, I can be disorientated and have no idea of the time.
