We all know the feeling: you wake up in the morning with the knowledge that you have been dreaming intensely. But no matter how hard you try, you can no longer piece together what exactly it was about. 

Against mental confusion

For science, dreams are still a largely unexplored field — because, for methodological reasons, it is extremely difficult to investigate the causes and content of dreams. Many dream researchers agree that forgetting dreams is important for mental well-being. If we could remember dreams just as well as waking experiences, it would create enormous confusion in our minds. Dreams mainly occur during REM sleep — a light sleep phase in which certain brain cells are activated. This process apparently prevents the storage of dream content in the hippocampus, a peanut-sized region deep in the brain that is essential for memory formation. As a result, dreams are quickly forgotten. 

Dreams full of emotions

And why are some dreams so chaotic or strongly emotionally charged? Studies have shown that during REM sleep, the limbic system — responsible for processing emotions — is more active than in the waking state. This may explain why many dreams contain emotions of varying intensity. On the other hand, the prefrontal cortex is less active than when awake, the brain region responsible for planning and logical thinking. This could explain why dreams often contain bizarre elements and why activities such as reading, writing, or working on a computer occur relatively rarely.