In a dream why do we wake up when we figure out that its not real. I mean even in a lucid dream we are lost to some extent and as soon as we stop accepting the situation we tend to awaken?
When you are dreaming, and you realize that it is a dream, the initial surprise can wake you up. However, you can build a skill for staying in the dream by anchoring yourself to simple actions in the dream. For example, as soon as you realize that you are dreaming, look at your hands and start shaking them in the dream. Generally, you will start to wake up, but then will feel yourself moving back into the dream. Once in this state of being fully aware of the dream and fully in the dream, you can start taking control of the dream.
There are several other techniques to help spot your dreams and help you remain in them to facilitate lucid dreaming. Here is a pretty decent article.
No dream is real, yet we dream without waking up, mostly.
In fact, you can argue the opposite - we wake up because we have the illusion our dream is real. Like when you wake up from a dream too distressful to take.
Our brain has two distinct modes:
- Stay on task (central executive).
- Dreaming (day or night).
While awake, we often in the stay on task mode, one of the key mechanism of which is the constant comparison of external stimuli to our mental beliefs (a constant "everything is as I expect it to be" check). Even while awake we drift into day-dreaming mode, and recent research has shown this happens much more frequently than we are conscious of.
While asleep, the dream mode is much stronger - we process little to no external stimuli (depending on the level of the sleep); the brain replays the day events; and there is strong random element to our cognitive processes. Yet, for the most part, we aren't in a vegetative state - the brain still needs waking up in case of true emergency.
Such emergency can be external (smoke alarm) or internal (truly dissonant dream).
So even whilst dreaming, it isn't quite "everything goes" - depending on the sleep stage, some backup mechanism is still in place. Approaching certain death, or having sex with your mother are two example of dreams that may cross the threshold and wake you up.