Myth & Folklore
The mare, the hag and the jinn: how one physiological event became a global folklore
Cultures with no contact with each other produced strikingly similar accounts of a nocturnal presence that pins the sleeper. The convergence is not coincidence, and the explanation is in the brainstem.
The English word nightmare has nothing to do with horses. The second element is mare, from Old English mære — a malevolent supernatural being that sits upon a sleeper's chest at night, suffocating and tormenting them.
The word has cognates across Germanic languages: German Mahr, Old Norse mara, Dutch nachtmerrie, Icelandic mara. The French cauchemar combines a verb meaning to press or trample with the same mare element. The image is remarkably stable: something comes in the night, and it presses down.
The same story, independently
What makes this more than an etymological curiosity is how widely the pattern recurs.
Newfoundland: the Old Hag. To be attacked is to be "hagged" or "hag-ridden". David Hufford's 1982 book The Terror That Comes in the Night documented the tradition and made the crucial argument — that the experience generates the belief, not the other way round.
Japan: kanashibari, literally "bound in metal", describing the immobility precisely.
Turkey: the karabasan — a dark presser.
Egypt and much of the Arab world: a jinn sitting on the chest.
Korea: gawi nulim — being pressed by scissors.
Thailand: phi am, a ghost that sits on the sleeper.
Nigeria (Yoruba): ogun oru, nocturnal warfare, understood in terms of spiritual attack.
Caribbean and parts of the American South: being ridden by a witch or a haint.
China: gui ya shen, ghost pressing on the body.
Mexico: se me subió el muerto — the dead one climbed on me.
Different pantheons, different cosmologies, no contact between many of them. The same three elements: immobility, a presence, and weight on the chest.
The standard anthropological assumption was that belief shapes experience — people who believe in hags experience hags. Hufford argued the reverse: a real, physiologically determined experience occurs independently of belief, and each culture supplies an explanation from its available materials. His evidence was that people with no prior knowledge of the tradition reported the same specific features, including details they had never heard described.
The physiology, briefly
Sleep paralysis occurs when consciousness returns while REM atonia persists. The person is awake, perceives the room, and cannot move. The dream-generating machinery is still running, producing hallucinations that overlay the actual environment.
The chest pressure has a specific explanation: during REM, breathing becomes shallow and largely diaphragmatic, and the intercostal muscles are atonic. Attempting to breathe voluntarily against inhibited musculature produces precisely the sensation of a weight preventing inhalation.
The sense of presence appears to arise from threat-detection systems activating in a state where the person can neither check nor flee — and hyperactive agency detection is a well-documented human bias, useful when the rustle might be a predator.
The art
Henry Fuseli's The Nightmare, exhibited in 1781, shows a woman thrown back across a bed with a squat incubus crouched on her chest and a horse's head emerging from the curtains. It caused a sensation, was widely reproduced, and remains the definitive visual statement of the experience.
The horse is generally understood as a pun on the English word rather than part of the older tradition — the mare was never equine — but it has since fed back into popular imagery, which is a nice example of folklore absorbing a mistake.
What it became
Several later traditions plausibly descend from the same source.
The medieval incubus and succubus — demons attacking sleepers sexually — map closely onto sleep paralysis phenomenology, including the paralysis, the pressure, and the sexual element that appears in a proportion of episodes.
Elements of the early modern witch trials involved testimony of nocturnal visitation and immobility that is difficult to read as anything else.
And the modern alien abduction narrative — paralysis, a presence in the bedroom, figures at the bedside, a sense of being examined, floating sensations — reproduces the classic phenomenology with a contemporary cast. Susan Clancy and Richard McNally's research on abduction experiencers found sleep paralysis to be a common feature of the reports.
Why this is worth knowing
It is a rare case where a folklore motif can be traced to a specific, identifiable, universal neurological event — where we can watch a physiological experience being converted into a supernatural explanation, repeatedly, by cultures that had no other tools available.
It also carries a practical point. Hufford's work, and Devon Hinton's later research with Cambodian refugees, found that the interpretive framework substantially affects how distressing the experience is. Believing you were attacked by a malevolent entity produces lasting fear. Knowing you experienced a well-documented dissociation between two normally simultaneous processes does not.
The mare has not gone anywhere. We just call it something else, and sleep better for it.
