Lucid dreaming. It's like being transported into a parallel life, a life you choose, a life where the laws of physics and social norms no longer exist, or better yet are under your control. Very few people have the capacity to stay conscious while sleeping. So what are the prerequisites for being a lucid dreamer?

While you'll find all sorts of tips on experiencing lucid dreaming online, German researchers have discovered that the ability is related to our capacity for introspection.

But let's start with a few definitions. Lucid dreaming is above all an ability to perceive one is dreaming and even influence one's dream. It means dreaming while knowing you are in a dream. And being able to influence dreaming is quite appealing to many people because it opens the doors to all sorts of possibilities. Our strongest desires and improbable things can be made a reality: meeting one's favorite actor, becoming president of the United States, flying like a bird, or walking through walls. Introspection in turn is part of the larger field of metacognition. It's the capacity we all have to access mental operations and to be conscious of our own cognitive processes. For example, you are aware of the intermediate calculations carried out when asked to solve the equation 28+14. You are also aware of the reasons that trigger you to adopt a particular behavior.

Two neuroscience teams from the Max Planck Institute, one in Berlin and the other in Munich, studied the brain structure of people capable of experiencing lucid dreaming on a frequent basis. By measuring the volume of gray matter located in different areas of the brain, particularly in the anterior prefrontal cortex, which plays an important role in the capacity for introspection, they were able to observe significant differences between lucid and non-lucid dreamers. And to confirm their hypothesis, they also observed greater brain activity in lucid dreamers during metacognition tests.

Determining cause and effect is another matter... Do lucid dreamers owe their ability to an above average capacity for introspection, or is the opposite true? To find out, the scientists will guide volunteers to experience lucid dreaming and then measure their capacity for introspection. But that's in a future study...