WasThere Something in the Cellar?

Steven T. Parsons (1), Ann R. Winsper (2) & Dr. Ciaran J. O'Keeffe (3)

1 Department of Psychology, Liverpool Hope University, Liverpool, UK.

2 Department of Psychology, Liverpool John Moores University, Liverpool, UK.

3 Universite de Toulouse, France

In recent years, infrasound (normally defined as acoustic energy with a frequency below that of normal human hearing i.e., 20Hz) has increasingly been suggested, although primarily anecdotally, as a causal factor in some reports of personal paranormal experiences. The seminal studies conducted by the late Vic Tandy at Coventry University (Tandy & Lawrence 1998; Tandy 2000), suggested that a frequency of around 19Hz may be a key frequency in the production of a range of physiological effects. These include eyeball oscillation which could lead to a smearing of vision which has been suggested as the cause of people experiencing apparitions.

In May 2006, the authors were invited to conduct large scale field experiments within Mary King's Close, Edinburgh (Mary King's Close forms part of Edinburgh's Underground City and this well known tourist attraction has a documented record of alleged paranormal and supernatural incidents going back to the 16th Century). After consultation with Mary King's Close, an experiment was devised that was to expose members of the public to a significant level (>55 dB(SPL)) of infrasound at a frequency of 19Hz. The experiment was designed as double blind with neither the experimenters nor the participants (and tour guides) knowing whether the infrasound was applied or not. Members of the public signed up for tours giving informed consent of their participation in an experiment. Participants were taken on a standard guided tour of the Close (groups of approx. 20), unaware of the presence or absence of applied infrasound. At the end of the tour, the participants were asked to fill in a questionnaire about their experiences during the tour.

The infrasound was applied using the ARIA system (Acoustic Research Infrasound Array), designed specifically to generate large amplitudes of infrasound at required frequencies between 12 and 25Hz at Sound Pressure levels (SPL) of up to 100dB(SPL). ARIA was positioned out of sight of participants in an area of the Close not accessed during the public tours. Measurements of infrasound levels at significant locations within Mary King's Close were measured prior to the participant's admittance using ARID (Acoustic Research Infrasound Detector) and found to be within the range 50-80dB (SPL). Ambient infrasound i.e., the infrasound normally present within the Close, was also measured, and found to be less than 40dB(SPL) throughout the Close at peak frequencies of less than 12Hz. This was caused by a mixture of local environmental noise i.e., road traffic, and an air conditioning unit located at the bottom end of the Close which supplied warmed air to the City Chambers building directly above the Close.

A total of 439 questionnaires were analysed, with 249 people experiencing both ambient and generated infrasound, and 190 people experiencing only ambient infrasound. From the preliminary results of the experiment, it would appear that a significant number of people reported experiences, regardless of the infrasound state (approximately one third of participants in the "on" condition, and in the "off" condition). However, in the "off" condition, people were more likely to report a single experience during their tour, whereas when infrasound at 19Hz was applied, significantly more people (36% compared to 16%) reported multiple (up to 4) experiences.

Of those reporting experiences, these included feelings of being watched, discomfort, anxiety and nausea. Perhaps the most interesting result was that when the infrasound was applied, 20% of people on the tour reported a perceived rise in temperature as opposed to just 5% of people reporting a perceived temperature rise when only ambient infrasound was present. No participant reported a drop in temperature, a phenomenon commonly associated with apparent paranormal experiences. However, out of 249 participants who received the generated 19Hz infrasound, only one reported any form of visual experience. This would suggest to the authors that the supposition put forward by Tandy in his two papers that 19Hz is a significant factor in the production of visual disturbances leading to apparitional experiences, is questionable. However, it is apparent from the results that whilst infrasound at around 19Hz is unlikely to create the visual field disturbances and thus apparitional encounters suggested by Tandy, it remains one of several possible causal factors in the production of a range of psychophysical experiences that may lead to a number of people reporting haunting experiences. This large scale experiment forms part of a larger series of field measurements of infrasound, partially funded by a generous grant from the SPR.

References

Tandy, V. (2000). Something in the cellar. JSPR 64, 129-140.
Tandy, V. & Lawrence, T.R. (1998). The ghost in the machine. JSPR 62 , 360-364.