Dreams are successions of images ideas emotions and sensations that occur involuntarily in the mind during certain stages Of sleep.
The content and purpose of dreams are not definitively understood,tHough they have been a topic of scientific speculation, philosophical intrigue and religious interest throughout recorded history.
The scientific study of dreams is called oneirology .
Science has proven to an extent that all mammals dream.
T scientific approach to dreams has been conducted through the discovery of REM sleep.
Dreams mainly occur in the rapid eye movement stage of sleep when brain activity is high and resembles that of being awake.
REM sleep is revealed by continous movements of the eyes during sleep.
At times, dreams may occur during other stages of sleep.
However these dreams tend to be much less vivid or memorable.
Dreams can last for a few seconds, or as long as twenty minutes.
A person is more likely to remember the dream if he or shIs awakened during the REM phase.