---
title: "The science behind sleep paralysis experiences described as encounters with demons"
url: "https://usubjects.com/article/the-science-behind-sleep-paralysis-experiences-described-as-encounters-with-demons-4460"
updated: "2026-10-30T16:06:20.290Z"
description: "The post highlights scientific explanations for sleep paralysis experiences commonly described as encounters with “demons.” No additional details or comment insights were provided in the supplied content."
sources: ["https://www.popsci.com/health/sleep-paralysis-demons-science/"]
licence: "All rights reserved"
---

# The science behind sleep paralysis experiences described as encounters with demons

Published: 2026-10-30  
Source: [r/abovethenormnews](https://www.popsci.com/health/sleep-paralysis-demons-science/)

### Overview

Sleep paralysis is a widely reported experience in which a person becomes conscious while temporarily unable to move. Episodes may include a sensation of pressure on the chest, intense fear and the impression that another being is present in the room. Across cultures, those sensations have often been interpreted as encounters with demons, ghosts, aliens or other supernatural figures. **Scientific accounts, however, describe sleep paralysis as a disruption in the transition between dreaming and wakefulness.**

Brian A. Sharpless, a clinical psychologist based in the Washington, D.C., area who has written extensively about the phenomenon, says he has documented more than 100 terms for sleep paralysis across different periods, places and cultures. Despite the varied language, he said the central experience is remarkably consistent: “Waking up, finding yourself unable to move, oftentimes a sense of pressure in the chest, a feeling of dread, fear, oppression.”

### A shared experience with different explanations

The physical sensations associated with sleep paralysis appear to be broadly similar, but their interpretation often reflects a person’s cultural environment. In Western traditions, episodes were historically linked to vampires, witches and ghosts. Germanic and Slavic folklore described a creature known as a **mare**—the origin of the word “nightmare”—that visited sleeping people, sat on their chests and left them unable to move.

A Danish painting by Joakim Skovgaard from the early 1890s depicts the mare as a shape-shifting supernatural being riding on a sleeper’s chest. In more recent accounts, the perceived visitor may instead be an alien or a “shadow person” standing in the corner of the room. Since the 1960s, reports from Tanzania have described a large winged figure called the Popobawa, said to attack people during episodes of paralysis.

These stories differ in their details, but they share a common structure: a vulnerable person is awake or partly awake, unable to control their body and convinced that a threatening presence is nearby. Researchers have proposed that this recurring pattern may result from the brain’s response to an unusual and frightening state of consciousness, rather than from an external entity.

### What happens in the brain

The scientific explanation centers on rapid eye movement, or REM, sleep—the stage in which vivid dreaming is especially common. During REM sleep, the brainstem temporarily inhibits most of the body’s muscles, leaving the muscles needed for breathing and eye movement active. This natural paralysis helps prevent people from physically acting out their dreams.

Sleep paralysis can occur when awareness returns before that muscular inhibition has ended. The person may be able to see and think, but remain unable to move or speak normally. “It’s kind of an uncanny, strange experience not to have control over your body,” Sharpless said. Surveys of people who have experienced sleep paralysis indicate that the episode is **almost always frightening**, in part because the individual cannot immediately explain or stop what is happening.

### Why a “demon” may appear

A perceived presence is one of the most consistent features of sleep paralysis. Scientists associate these figures with what researchers call the **threat-activated vigilance system**, a brain response that becomes alert to possible danger. In the context of paralysis, fear, restricted movement and dream imagery may combine to produce a vivid impression of an intruder or attacker.

The identity of that figure can vary according to cultural expectations and personal beliefs. A person familiar with stories about demons may interpret the presence in those terms, while someone influenced by modern accounts of extraterrestrial encounters may describe an alien. The changing imagery, researchers argue, helps explain why similar bodily experiences have generated different supernatural traditions across history.

Understanding the phenomenon does not make an episode less disturbing, but it offers a non-supernatural framework for the experience. **Sleep paralysis is a recognized interaction between REM-related muscle inhibition, partial awakening and the brain’s response to perceived threat**—one that has been given many names, but appears to share a common biological foundation.

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