"Dreaming usually occurs in the R.E.M. stage (rapid-eye movement) of sleep, in which brain activity is high and signaled by rapid horizontal movements of the eyes. Sometimes dreams occur during the other stages of sleep; however, these are much less memorable and less clear. They can sometimes last for a few seconds, or as long as twenty minutes. Dreams are a symbol and link to the inner core of the human subconscious." Everybody dreams every time they sleep deeply, they just don't always remember it.