According to Freud, we dream to satisfy unconscious desires or wishes, especially those involving sex and aggression.
Chronic stress can cause the physiological exhaustion if combined with generalized helplessness renunciation of search.
Those that take the cognitive approach to dreaming believe that the mind is the center of all dreams. While we can now investigate sleep and related phenomena, not all researchers agree on exactly why we sleep.
Many other researchers and psychologists have built and expanded Hobson's original theory. Search activity and body resistance, then, create a natural positive feedback, supporting progress, development, and evolution. They will have a blank stare and still be able to perform complex tasks.
Then, in a sense dreams provide clues to the person's problems, concerns, and emotions Plotnik, The brain system related to search activity to orienting response, novelty detection etc.
How does the brain get itself out of this abyss in the absence of external stimulation? He suggested that this is because we have two psychological processes at work at the same time when we try to suppress a thought: an operating process that actively suppresses it, and a monitoring process that keeps an eye out for the suppressed thought.