Allan Cheyne

Allan Cheyne is a Canadian psychologist at the University of Waterloo, Ontario, whose survey-based research into sleep paralysis produced the field's most influential empirical account of why the experience so often gets described in supernatural terms.

Approach

Cheyne's contribution to anomalistic psychology rests on a methodological shift: rather than working from small clinical or field samples, as earlier researchers had, he recruited sleep paralysis experiencers through large online surveys, running into the thousands of respondents. That scale let him treat the phenomenology of the experience as a dataset — tracking which sensations occurred, how often, and in what combinations — in a way case studies alone couldn't support.

The three-category model

Cheyne's best-known work formalised a three-part taxonomy of sleep paralysis hallucinations. Earlier researchers had gestured at the same categories; Cheyne gave them empirical weight.

Intruder hallucinations

The most commonly reported experience: an overwhelming sense that something else is in the room, whether glimpsed, heard, or simply felt. Cheyne linked it to amygdala-driven threat detection firing during conscious paralysis, with dream content bleeding into waking perception.

Incubus hallucinations

Chest pressure, breathlessness, and a sharpened sense of danger — often experienced as something sitting on the sleeper. Cheyne showed this typically builds on the intruder hallucination, with real respiratory restriction during paralysis feeding hallucinated content generated by an already-aroused brain.

Vestibular-motor hallucinations

Floating, spinning, flying, or leaving the body. Cheyne tied these to disrupted vestibular processing and body ownership during the REM–wake transition, connecting them to the wider literature on out-of-body experiences.

Cross-cultural significance

The pattern Cheyne identified is that this three-part structure recurs, almost unchanged, across unrelated cultural traditions: the Old Hag of Newfoundland folklore recorded by David Hufford, kanashibari in Japan, djinn-visitation accounts in Islamic tradition, the European mare, and modern alien abduction reports all map onto the intruder and incubus categories. The vestibular-motor category turns up in out-of-body accounts and, in some traditions, shamanic flight.

That consistency — one neurological mechanism, dressed in whatever supernatural vocabulary a culture has on hand — is one of the clearer pieces of evidence in anomalistic psychology that ordinary brain processes can produce experiences indistinguishable, from the inside, from a genuine encounter.

Relevance to paranormal claims

Cheyne's findings give weight to the argument that a meaningful share of reported paranormal encounters — bedroom apparitions, night visitations, abduction narratives, demonic attacks — are sleep paralysis events filtered through whatever supernatural framework is culturally to hand. His work also reinforced a broader finding in hallucination research: vivid, externally projected perceptions of presences and figures are far more common in neurologically ordinary people than clinical models used to assume.

See also

• Sleep paralysis
• Hallucination
• Anomalistic psychology
• Old Hag