Eccentric artist Salvador Dali believed that one of the secrets to becoming a great painter was what he called “slumber with a key.” “Slumber with a key” was an afternoon siesta designed to last less than a single second.

To accomplish this micro nap, Dali would sit in a chair with his arms resting on the armrests and his wrists dangling over them. He held a heavy metal key between the thumb and forefinger of his left hand, and placed an upside-down plate on the floor directly below the key. The instant Dali dozed off, the key would slip through his fingers, clang the plate, and awaken him from his nascent slumber. In that moment, Dali observed, one walked “in equilibrium on the taut and invisible wire that separates sleep from waking.” The artist recommended this practice to anyone who worked with their mind, believing that the tiny nap “revivified” one’s whole “physical and physic being” and left you invigorated and inspired for an afternoon of creative labor.

Dali said that he had learned the “slumber with a key” trick from the Capuchin monks and that other artists he knew also used it.

The secret Dali had discovered involves entering a state called hypnagogia. Today we’ll discover what’s behind it, as well as how you too can discover new dimensions and insights along the boundary between wakefulness and sleep.

Hypnagogia and the Hypnagogic Nap

A regular sleep cycle consists of four stages. In the first, we’re technically not asleep, but are on our way. We spend about 5 minutes in Stage 1 sleep, though it can last longer. Brain activity begins to slow down; body temperature starts to drop; muscles relax; eyes move slowly from side-to-side. We lose awareness of our surroundings but we’re still easily jarred to wakefulness. If you’ve ever been woken just as you were dozing off, and claimed you were only “resting your eyes,” you were likely roused during Stage 1 sleep.

The experience of this transitional state between wakefulness and sleep is called hypnagogia. You’re floating at the very threshold of consciousness; your mind is sliding into slumber, but still has threads of awareness dangling in the world. You’re truly “half-asleep.”

While you’re in this state, you may see visions and hallucinations (often of shapes, patterns, and symbolic imagery), hear noises (including your own name or imagined speech), and feel almost physical sensations that relate to what you spent the day doing (like swimming in waves or riding in a boat). You may feel like you’re bobbing, floating, or falling (which is why you sometimes wake up from Stage 1 sleep with a jerk). The experience can essentially be described as “dreaming while awake.”

Hypnagogia can be experienced both when you’re transitioning to falling asleep, and again when passing through Stage 1 on the way to waking up (it is then called hypnopompia). In fact, because you repeatedly ascend and descend through the sleep cycle over the course of a given night, and even experience a few brief awakenings, you likely delve into hypnagogia at those times too; I know Kate has reported receiving revelatory-like answers to questions in the middle of the night in the midst of one of these half-asleep/half-awake states.

However, one’s memories of the hypnagogic states experienced during the night and as you rise in the morning are often plagued by grogginess and forgetfulness. Moreover, the hypnagogic state you pass though as you’re first falling asleep for the night will likely be forgotten by the time you arise in the morning. It’s for that reason that Dali and many other creative types experimented with intentionally inducing hypnagogia as part of a micro-nap during the day. By so doing, they could purposefully wake themselves up right before crossing the threshold into Stage 2 sleep, and immediately write down the insights that had arisen during their brief slumber. They found that these “hypnagogic naps” boosted their creativity and opened their minds to new insights and solutions to problems.

Why would the hypnagogic nap have such an effect? The answer largely remains a mystery, as Stage 1 sleep generally, and hypnagogia specifically, have not been well-studied. The hypothesis is that the state allows for the fluid mixing of the things one has been working on during the day, with dreamlike thoughts — the collision of the conscious and the unconscious. Professor Andreas Mavromatis argues that during hypnagogia, the “newer” (evolutionarily speaking), rational parts of the brain are inhibited, while the “older,” more primitive parts (which think in imagery and symbolism rather than words and well-defined concepts), have freer rein. The usual dominance of the prefrontal cortex and its rules of logic are checked, and the typical constraints placed on what’s possible are loosened. Thus, the mind is free to play around, make associations between divergent ideas, and come up with imaginative solution to problems.

Famous Men Who Took Hypnagogic Naps

However it works, many great men from history who produced amazing innovations in science, math, music, art, and literature swore by the power of the hypnagogic nap. The practice has been around at least since the time of Aristotle, and was particularly popular during the Romantic Age, which prized the pursuit and discovery of intuitive insights.

William Blake and John Keats had visions during their wakeful-dreaming that inspired their poetry. Keats’ “Epistle to John Hamilton Reynolds” begins with a description of the hypnagogic state: