Mary Shelley was inspired to write Frankenstein during a dream. Otto Loewi woke from a dream in the middle of the night in 1920 and wrote out an experimental design that allowed him to test if nerve impulses were the result of chemical transmission instead of electrical transmission; this work won him the Nobel Prize in 1936. Paul McCartney wrote the song “Yesterday” upon awaking from a dream. Friedrich August Kekulè formed the chemical “Structure Theory” and envisioned the ring structure of benzene during dreams. When people are stuck on problems in their everyday lives, a common suggestion is “sleep on it”, but what is the brain really doing while a person dreams? Teams at the University of California, San Diego and the University of Southern California are trying to answer that very question. Doctor Sara Mednick and colleagues at both institutions published a paper in the journal PNAS in May which provides evidence for the idea that it really is dreams, or REM sleep, that is responsible for boosting creative problem solving.

              Mednick and colleagues compared the effects of REM sleep, non-REM sleep and quiet rest on creativity and memory. They found that all three could increase memory performance, but only REM boosts creative problem solving skills. So, just how do scientists measure creativity? Participants in a study are given word association tests with seemingly unrelated words to see if they can come up with an appropriate linker. A person might see: “Heart, Sixteen, Cookies.” If “Sweet” pops into their head it is a pretty good sign that their creative juices are flowing.

              But, whether or not a person can connect unrelated ideas in an unexpected way the first time they see them is really a reflection of their baseline creative problem solving ability. Dream epiphanies are usually associated with solving problems that a person has been mulling over for a while. This was also the case in the study. If participants had no previous experience with the words, the type of sleep they had did not make a difference on their creative performance, but if the participants were “primed” before they slept then the ones who achieved REM sleep performed significantly better on the creative problem solving test. Priming participants is achieved by engaging their brain with words they will need later for the creativity test without directly providing the answer. For example, to prime "sweet” the authors could give the participants a long list of analogies, one of which would be "chips: salty, candy: sweet.” By activating this node in the brain and then allowing participants to enter REM sleep their creative problem solving was boosted, but a group given the exact same priming who were only allowed non-REM sleep or quiet rest did not show any improvement.

              The authors needed to rule out the possibility that participants who experienced REM sleep experienced better memory recall, contributing to their ability to use the priming more effectively than the other groups. When these groups were tested on memory before and after sleep they all did comparably to each other, suggesting that the increased creative problem solving ability of the REM group compared to others was not just the result of increased recall of the words.

              Mednick and colleagues describe a “spreading-activation” model based on their results.  In this model, during a dormant period -such as REM sleep- the brain takes activated nodes, areas that have been engaged during the day, like "sweet" in the example above, and spreads the activation to associated nodes, like "heart", "sixteen" or "cookies". This makes it more likely that a person would be able to form a connection when they awake. In this way REM sleep allows people to integrate new experiences and input into their past experiences, leading to “ a richer network of associations for future use.”

              During REM sleep levels of certain chemicals in the neocortex become lower. These chemicals normally suppress recurrent connection formation in that area of the brain. The Mednick lab posits that the decrease of these chemicals during REM sleep may provide an environment in which reorganization and restructuring of associations becomes much easier for the brain.  Just how to test this hypothesis may be something the Mednick lab has to sleep on. 

              Dreams have a somewhat mystical reputation in human culture. They have been called messages from the gods, a metaphysical stream connecting all people, and a window into a person’s true feelings and desires. Research into what really happens in the brain while a person is dreaming may help society understand why dreams seem so important.

To read the paper, click here.

You can also visit SaraMednick.com for more information.