Well-organized, systematic studies of apparitions started after the Society for Psychical Research (SPR) was founded in England in 1882. The SPR was soon joined in this quest by the American Society for Psychical Research (ASPR) and by smaller research groups and individual investigators in continental Europe. Scholarly journals were established to publish ongoing research as well as theoretical speculation and fierce debates. The basic idea of these efforts was to apply the scientific method to data collection, evaluation, and interpretation of psychic phenomena – an area which nineteenth-century materialistic science had ignored up to that time.
Advertised appeals brought an abundance of material, much of it reported in the Proceedings and Journals, leading in 1886 to the publication of the voluminous Phantasms of the Living. This was followed by a landmark Census of Hallucinations, whose findings were published in the Proceedings in 1894.
It was a pioneering survey, 17,000 respondents were contacted. The reports were analyzed and published in several major works. The main analysis done by Edmund Gurney was published in two volumes called Phantasms of the Living. Other important was written by Gurney et al (1886) and Myers (1903). Several other collections appeared later, such as those by Bennett (1939), Green and McCreery (1975), Jacobson (1973), and Jaffé (1979).
With the benefit of hindsight, several conditions pertaining in the late nineteenth century can be seen to have been peculiarly conducive to research into ghostly phenomena.
The simple fact is that they discovered that 70 to 90% of all reported cases of ghostly phenomenon is actually explainable. Additionally, they used the information they uncovered to create a classification system for the reported accounts of hauntings. The classifications they created to consist of only two types, "Low Grade" and "High Grade".
Low Grade (explainable):
Apparitions are most often reported by "fantasy-prone" persons, the 4% of the population who are good hypnotic subjects, have vivid imagery skills, and who report a wide range of other psychic and or paranormal experiences. Low-Grade cases/observations are often explainable by one or more of the following factors.
The report has little merit, being based on distortions of perception (e.g., because of poor light, short duration, pareidolia), and on emotional exaggerations. Hoaxes can be common, especially for ghost photographs. Misperception is misinterpreting something seen, heard, felt or otherwise sensed. Misperception alone accounts for most of the reported paranormal experiences.
b) Imagery or Hallucination
The witness, often psychic or a suggestible person unconsciously generates an apparition as a response to suppressed needs or beliefs. The source of the impressions would be the conscious or unconscious mind of the witness, or more speculatively, archetypal images from the "collective unconscious". An old variant is the model of Gurney (1886) and Tyrrell (1953), now called the super-ESP hypothesis; the apparition is at least partly composed of telepathic data that is then projected out from the mind of the witness. Louisa Rhine found that input of data from outside was unnecessary in all but one of 8000 reports; apparitions were hallucinations created totally within the mind (Falsidical Hallucination).
The most typical examples of Falsidical Hallucinations are moving shadows (Shadow people) and fleeting images typically lasting less than two seconds. It is important to understand that the witness did actually have an experience and will strongly believe so, however, the experience is explainable. A measurement of the witness’ bias (belief) towards the paranormal can often correlate directly to the potential of experiencing a Falsidical Hallucination. The hallucination may also trigger the fight or flight response in the witness.
c) Myth Building and hoaxes
The account of the phenomenon is comprised of second and third-hand accounts. There are no direct witnesses to the reported paranormal activity.
Myth building is the elaboration of elements in a story. These elements may have some degree of truth while others may be completely false. It is the essential building blocks used in the construction of myths and urban legends.
The designation suggests nothing about the story's veracity, but merely that it is in circulation, exhibits variation over time, and carries some significance that motivates the community in preserving and propagating it. Essentially, it is nothing more than a ghost story.
High-Grade observations include veridical information that is revealed to the witness/witnesses about the apparition's appearance. Details such as specific clothing, facial/body features, injuries, movements (having a distinct walk or limp) and smells (such as the distinct smell of specific lady's perfume that the deceased person wore in life) that can be confirmed or compared with the reports of other witnesses are vital. Other elements which can make an observation High Grade include;
- They reappear in the same place over time to different witnesses. The phenomenon repeats the behavior.
- The apparition is seen in a specific location (the place of death or a great tragedy) and if veridical information from that sighting is later verified as factual about the deceased, such as matching their description with an old photograph, being told who killed them, the location of valuables, or specific phrases known being uttered which matches their personality that known only to living relatives/friends.
- Observations where multiple people, either together or independently, describe the exact same details of the phenomenon they have witnessed. This is especially important if they had no prior knowledge of the location or its history. If the apparition is unknown to the witness at the time of the sighting but was identified by other means that identifies it as a factual person. This may have been obtained through historical research or when the witness or witnesses speak to other people like relatives and friends or see them in a photograph.
- The apparition either directly tells them or shows them something important (a family secret, a lost will, how they died, who killed them, etc) that is later independently verified to be true.
- The duration of the sighting is over three seconds and the witness can make out enough visual details to provide a good description.
The above types of Veridical Encounters highly suggest that when you examine them, many contain strong veridical elements aside from merely "seeing a ghost". However they are very rare and the burden of proof is harder to obtain, as these are subjective experiences.“Grading” cases and observations and understanding the results of prior research is a vital part in the examination of paranormal claims as it dictates the direction and methodology an investigator should use to examine the available testimony and evidence to reach a conclusion.
Low-Grade cases are often explainable by properly identifying the reported phenomenon as natural or manmade in origin. High-Grade cases are much more difficult to tackle and will present more of a challenge.