Although there is no scientific evidence to prove why people dream, many researchers believe that dreams promote psychological health, improve memory and learning, and represent our unconscious desires. Regardless of the reason, humans dream every night, even when they do not remember their dreams in the morning.
Dreams occur during the rapid eye movement period of sleep, also known as REM, which occurs for 90 minutes at a time during sleep. An individual generally has three to four REM cycles per night. During a REM cycle, brain neurons are more active than usual and the brain begins to produce dreams.
Some researchers believe that there is nothing psychological about dreams, but that they are merely the biological response to a body's random signals and movements during sleep. Other researchers believe that dreams have a profound impact on how people process the waking day, feel about the present and prepare for the future. Many popular theories explore the idea that people dream of things they wish would happen or fear would happen, and that dreams can reveal a lot about subconscious desires and fears. Regardless of the meaning of dreams, scientists agree that dream intensity decreases with age, beginning in early adulthood.