As you sleep, your body rehearses, relives and prepares for countless different scenarios, in a process commonly known as dreaming. While to us they seem like meaningless snatches of fantasy worlds that are often as frightening as they are wonderful, many scientists now theorize that they have a far greater importance than solely an outlet for the imagination.

In the early 20th century, Austrian psychologist Sigmund Freud was the leading expert on dreams. He believed that the content of a person’s dreams represents their socially unacceptable repressed desires and stressed the symbolic nature of different dreams. For example, Freud believed that dreaming about falling meant that one’s life was out of their control and a dream about one’s teeth falling out represented a loss of power.

However, Freud’s theories were soon replaced by the ideas of his student and protégé, Carl Jung. Jung believed that as people dream, they reflect on their waking lives and explore potential solutions to their problems; essentially practicing for the future.

This “practice” occurs during the fifth stage of sleep, known as Rapid Eye Movement, or REM, for the frantic fluttering of the sleeper’s eyes that is common during this stage. While dreams are more common, intense and memorable in this stage, they can occur throughout the sleep cycle. In fact, as a result of the intense dreams experienced during REM, the brain actually releases the amino acid glycine onto the spinal cord, effectively paralyzing the body to prevent it from acting out dreams.

It was this natural safety system that tipped researchers onto what many believe proves that dreams are more than snatches of electronic impulses translated into nonsensical images by the brain. If dreaming did not play some important role in the human consciousness, many researches argued, why would such drastic measures have been taken to ensure that the human body did not hurt itself while experiencing them?

Further studies have shown that when someone studies a new subject or practices a new skill soon before sleeping, their level of understanding greatly increases after sleeping, as the information is internalized and processed by the brain, demonstrating how important sleep is for performance in school and athletics.