The Incubus
The demon lover of the night, and the sleep that cannot move.
In the Texts
The manuals know two night visitors: the nightmare that sits on the chest, which Canale treats among the afflictions of the bewitched, and the incubus and succubus, demons who lie with the sleeper, which the Malleus discusses at length and della Riviera returns to in the Mondo magico. The signs are the weight, the inability to cry out or move, the sense of a presence, and, for the incubus, the sexual act felt and sometimes consented to. The exorcists distinguish the dream from the deed by the emission, which they take as proof.
What Medicine Makes of It
Sleep paralysis, the REM atonia that persists into waking, with hallucinations that follow a fixed order: a sensed presence, a figure, pressure on the chest from the struggle to breathe against paralysed muscles, and in a minority a sexual content, which Cheyne (2003) sorted into intruder, incubus, and vestibular experiences in a thousand subjects. The emission is the REM erection, which Fisher recorded in nearly every REM period in 1965, and the nocturnal emission is universal in men. The visitor brings nothing, which the Malleus, with its stolen seed, had worked out.
The Evidence
- Cheyne (2003), in 1,000 subjects, sorted the hallucinations of sleep paralysis into three groups: the intruder (a sensed presence, footsteps, a figure), the incubus (pressure on the chest, choking, assault, sexual sensations), and vestibular-motor experiences (floating, flying, leaving the body); the incubus group tracks the respiratory struggle against the paralysed muscles.
- Hufford’s fieldwork in Newfoundland (1982) found the “Old Hag” attack in 23 per cent of adults, with the same features in those who had never heard the tradition, and argued that the experience generates the belief rather than the belief the experience.
- Sharpless and Barber’s meta-analysis (2011) put the lifetime prevalence of sleep paralysis at 7.6 per cent of the general population and 32 per cent in psychiatric patients; the sexual content is reported by a minority and is more often distressing than pleasurable.
- Nocturnal emissions, which the manuals attributed to the succubus, occur in the great majority of adolescent and adult men and were measured in Kinsey’s sample (1948); they coincide with the erections of REM sleep, which Fisher, Gross, and Zuch recorded in 1965 as occurring in nearly every REM period.
- Kramer and Sprenger devote Malleus Part II, question 1, chapter 4 to incubi, and accept that the witch’s child by a demon is conceived with stolen human seed, which is to say that the manuals themselves knew that the visitor brought nothing of his own.
Where They Part
The manuals read the experience as an act done to the sleeper by another; the laboratory reads it as the sleeper’s own body, half awake. Both agree that it is not a dream, and the terror is the same.
In the Materia Medica
Sources
- Cheyne, J. A. (2003). “Sleep paralysis and the structure of waking-nightmare hallucinations.” Dreaming 13.
- Hufford, D. J. (1982). The Terror That Comes in the Night. University of Pennsylvania Press.
- Fisher, C., Gross, J., and Zuch, J. (1965). “Cycle of penile erection synchronous with dreaming (REM) sleep.” Archives of General Psychiatry 12.
- Kramer, H., and Sprenger, J. (1487). Malleus Maleficarum, II.1.4.
Historical and interpretive; not medical advice.