Studies

The SPR Census of Hallucinations

Also Known As Census of Hallucinations

Citation Formats

General Reference

Divinity Atlas. "The SPR Census of Hallucinations." Accessed August 30, 2026. https://dev-divinity.interactiveatlas.org/studies/the-spr-census-of-hallucinations.

APA Style

Divinity Atlas. (n.d.). The SPR Census of Hallucinations. Retrieved August 30, 2026, from https://dev-divinity.interactiveatlas.org/studies/the-spr-census-of-hallucinations

BibTeX

@misc{divinityatlas-the-spr-census-of-hallucinations,
  author = {Divinity Atlas},
  title = {The SPR Census of Hallucinations},
  year = {2026},
  url = {https://dev-divinity.interactiveatlas.org/studies/the-spr-census-of-hallucinations},
  note = {Accessed August 30, 2026}
}

The census is the most ambitious piece of empirical work the Victorian psychical researchers attempted, and it is the point at which their programme comes closest to ordinary social science. Rather than collecting striking stories, the committee tried to establish a rate in the general population, which is the right instinct: a coincidence is only interesting against a base rate, and nobody had one. Seventeen thousand responses was a substantial undertaking in the 1890s. The weaknesses are equally clear and were pointed out at the time. The sample was not random, the question invited people with something to report to answer it, and the memory of an experience is reshaped once its apparent confirmation is known.

Facts

Disputed

Principal Critic

The chance baseline assumes an apparition and a death are independent events, which fails in exactly the cases most likely to be reported, and the twelve-hour coincidence window is an analytic choice 2

Henry Sidgwick, Eleanor Sidgwick, Alice Johnson, Frederic Myers and Frank Podmore conducted the Society for Psychical Research's Census of Hallucinations in the 1890s, putting a single standard question to roughly seventeen thousand respondents and finding about one in ten answered affirmatively that they had experienced a waking hallucination of a living or dead person. Alan Gauld's The Founders of Psychical Research (1968), a history of the Society's early investigative methods, records that the survey's headline incidence finding has held up well under later scrutiny, a large sample answering one clear question being comparatively robust survey work for its period. What Gauld and later critics dispute is the inference the original investigators drew, that the rate of hallucination coinciding with a death exceeded chance by an amount suggestive of a paranormal connection, since establishing that depends on independently and reliably dating the deaths against the reported hallucinations, a harder problem than counting the affirmative responses. The method throughout is documentary and statistical re-examination of the original survey's own tables, and the principal critique concerns the coincidence calculation rather than the incidence figure.

Method

Sample Size

Roughly seventeen thousand responses to a single standard question, of which about one in ten was affirmative 1

The sample was not random: volunteers put the question to people they already knew.

Investigators

Henry Sidgwick, Eleanor Sidgwick, Alice Johnson, Frederic W. H. Myers and Frank Podmore 1

Taken from the study's own record of who conducted it.

Evidence

Replication Status

Never repeated on a comparable scale. The calculation has been criticised since publication for relying on retrospective self-report, for a contestable chance baseline, and for a sample gathered by volunteers approaching people they knew. 1

The study's replication record as reported in the literature. Where replication failed or is disputed, that is stated rather than softened.

Learn More

Asking Seventeen Thousand People One Question

The committee's reasoning was sound and, for its date, unusual. Reports of seeing an absent person at the moment of that person's death were the society's central category of evidence, and the obvious objection was coincidence: in a large population, apparitions and deaths will sometimes fall on the same day. Answering that objection requires two numbers, how often people have such experiences at all and how often they coincide with a death, and nobody had either. So the committee went and collected them. Volunteers put a single standard question to people they could reach: had the respondent ever, when believing themselves completely awake, had a vivid impression of seeing or being touched by a living being or inanimate object, or of hearing a voice, which so far as they could discover was not due to any external physical cause.

Roughly seventeen thousand answers came back. About one in ten was affirmative. The committee then worked through the affirmative cases, isolating those in which the figure was recognised and the person concerned had died within twelve hours, and compared the resulting rate against the national death rate. Collecting seventeen thousand responses by hand, through volunteers with no funding and no postal survey apparatus, took the committee roughly five years.

What the Arithmetic Rests On

The committee concluded that death-coincident apparitions occurred vastly more often than chance allowed, and the objections to that conclusion arrived immediately and have not been improved on much since. The sample was not random: volunteers asked people they knew, and a person with a story to tell is more likely to answer than one without. The data are retrospective self-report, sometimes about events years earlier, and memory reshapes a vague impression into a specific one once the outcome is known, dating it more precisely than it deserves. The twelve-hour window is an analytic choice, and a different window gives a different rate. And the comparison assumes the two events are independent, which fails in exactly the cases most likely to be reported, since someone whose relative is gravely ill is both more likely to think about them and more likely to have them die.

None of this makes the census worthless. It remains the only attempt anyone has made to establish a population rate for the experience, and its raw finding, that roughly one person in ten reports a waking hallucination at some point, has held up reasonably well against modern surveys. It is the inference to coincidence, not the survey, that the criticism reaches.

Cross-Tradition Connections