Sleep and creativity
The majority of studies on sleep and creativity have shown that sleep can facilitate insightful behavior and flexible reasoning. On the other hand, a few recent studies have supported a theory of creative insomnia, in which creativity is significantly correlated with sleep disturbance.

# Sleep and creativity studies

## REM sleep as a state of increased cognitive flexibility
In a study on cognitive flexibility across the sleep-wake cycle, researchers discovered that when woken from REM sleep, participants had a 32% advantage on an anagram task (when compared with the number of correct responses after NREM awakenings). This was consistent with the hypothesis that due to the lack of aminergic dominance in REM sleep, this particular sleep state is highly conducive to fluid reasoning and flexible thought. Interestingly, participant performance after awakening from REM sleep was not better than participants who stayed awake, which indicates that in REM sleep, there is an alternative (but just as effective) mode of problem solving that differs from the mechanism available while awake.

## Sleep facilitates insight
Participants in a study were asked to translate a string of digits using two simple rules that allowed the string to be reduced to a single digit (number reduction task). Out of three groups of participants (those who slept, those who stayed awake during the day, and those who stayed awake during the night), participants who got eight hours of sleep were two times as likely during retesting to gain insight into a hidden rule built into the task.

## Lack of sleep impairs creativity
Some participants in a study went 32 hours without sleep while the control participants slept normally. When tested on flexibility and originality on figural and verbal tests, the sleep-deprived participants had severe and persistent impairments in their performance.

## More creativity in humor while asleep
Under hypnotic induced sleep, participants were much more likely to produce paraphrases of jokes that they had heard before and to spontaneously create new jokes (when compared with their performance while awake).

# Creative insomnia
Creative insomnia refers to the idea that insomnia can actually spark creativity.

## Anecdotal accounts of creative insomnia
- Marcel Proust wrote most of his A la Recherche du temps perdu (In Search of Lost Time) while staying awake in the night due to a chronic illness. In Sodome et Gomorrhe, he suggests that "Un peu d'insomnie n'est pas inutile pour apprecier le sommeil, projeter quelque lumiere dans cette nuit. "
- Film maker Alan Berliner made a documentary on his lifelong insomnia and its complex role in his creative process.
- "Insomnia is almost an oasis in which those who have to think or suffer darkly take refuge." - Colette
- "It's at night, when perhaps we should be dreaming, that the mind is most clear, that we are most able to hold all our life in the palm of our skull.  I don't know if anyone has ever pointed out that great attraction of insomnia before, but it is so; the night seems to release a little more of our vast backward inheritance of instincts and feelings; as with the dawn, a little honey is allowed to ooze between the lips of the sandwich, a little of the stuff of dreams to drip into the waking mind.  I wish I believed, as J. B. Priestley did, that consciousness continues after disembodiment or death, not forever, but for a long while.  Three score years and ten is such a stingy ration of time, when there is so much time around.  Perhaps that's why some of us are insomniacs; night is so precious that it would be pusillanimous to sleep all through it!  A 'bad night' is not always a bad thing." - Brian W. Aldiss
- Acquainted with the Night: Insomnia Poems (edited by Lisa Russ Spaar) is a collection of over eighty poems by famous poets and writers like Walt Whitman, Emily Bronte and Robert Frost, all inspired by sleepless nights. Fifteen of the poems actually have "insomnia" in the title.
- "Si les insomnies d'un musicien lui font creer de belles oeuvres, ce sont de belles insomnies. " - Antoine de Saint-Exupery
- Vladmir Nabokov believed that insomnia was a positive influence on his work. He once remarked that "sleep is the most moronic fraternity in the world, with the heaviest dues and the crudest rituals."

## Studies that support creative insomnia
Although no studies have actually shown a causal relationship yet, various studies have suggested that the positive relationship between sleep and creativity to be more complicated and less clear-cut than previously thought.
- One study with children (ages 10-12) in New Zealand demonstrated a correlation between insomnia and creative thought. This study looked at the incidence of sleep disturbances in thirty highly creative children when compared with thirty control children. The hypothesis was that there would be a higher incidence of sleep disturbance in the highly creative children than in the control children. Results showed that there was a significant difference between the two groups, with the creative children reporting more sleep disturbance, therefore suggesting that creative ability may indeed affect an individual's sleep patterns. More specifically, out of the sixty children tested on a standard creativity test, seventeen of the highly creative children indicated that they had higher levels of sleep disturbance (compared to only eight of the control children).
- In another study that examined the interactive relationships between sleep, fatigue, creativity and personality, participants were given the Sleep Questionnaire, the Fatigue Inventory, the Remote Association Test and the Probabilistic Orientation Test. The researchers found that arousal measures of sleep and fatigue were meaningfully related to one another, but not to measures of thinking and of attitudinal orientations. Most importantly, they found that creativity was not significantly related to any of the dimensions of sleep.

## Studies that reject creative insomnia
- In a series of three studies that analyzed the link between creativity, dreams, and sleep behaviors, researchers discovered that (1) participants who were classified as "fast sleepers" (those who fell asleep quickly) were more likely to score highly on a creativity test, (2) participants who scored highly on a creativity test were more likely to solve their problems through dreams and to fall asleep quickly, and (3) adults in creative occupations have significantly more dream distortion, visual mentation, and regressive dream content.