Most ghostly encounters center on location. They are more likely to occur in a 19^th Century three-story New England mansion than in subdivision ranch home, and much more likely than at a Sav a Lot. They occur in homes built on former Indian burial grounds, but probably not on the site of a former fabric store. Also relevant is the time of day, as most ghostly encounters occur at night.

However, there may be larger factor than location, time, or even expectation. This was addressed in an article in Cracked, which has undergone one of the more amazing transformations in U.S. pop culture history. Once a Mad Magazine clone, it is now an online source with insightful articles on a broad range of topics featuring humor, intelligence, and social commentary.

And one of its articles told the tale of how a lab assistant’s ear bleed led to a potential discovery about what really happens during ghostly experiences. Scientist Vladimir Gavreau noticed his assistant was bleeding from the ear and, in the spirit of discovery and strangeness, put various vibrating pipes near the assistant and discerned that pipes of a certain length and weight led to mental and physical discomfort for the assistant. Garvrea had discovered infrasound, which is noise whose frequency is low enough that humans can sense it but not hear it. The hypothesis is that it drives a person bonkers to receive sensory input without knowing where it’s coming from.

This was put to scientific, albeit unethical, test when low frequency sounds were unleashed on an unwitting concert audience, with 22 percent reporting feelings of dread, chills, and depression. Researchers have found that sounds between seven and 19 Hertz can elicit these symptoms, along with nausea, disorientation, and loss of equilibrium.

A more proper test was conducted by engineer Vic Tandy after he and fellow researchers experienced all these unpleasantness in their laboratory. For added spookiness, they were also seeing gray shapes out of the corner of their eyes. Tandy deduced that these experiences were confined to a specific section of the laboratory. Also in this location, metal sheets would vibrate uncontrollably when placed in a vice.

He traced the culprit to an air conditioner ventilator emitting low frequency vibrations that bounced off the lab’s walls at 18.9 Hertz. It was even powerful enough to cause the blurry peripheral vision because the vibrations were subtly affecting the eyeballs. Once the ventilator was removed, the fear and apparitions disappeared.

Tandy further tested this idea in an allegedly haunted abbey. Local lore had it that visitors to the abbey cellar would become nauseous and see gray ghostly images in their periphery. Tandy investigated and learned the cellar’s shape was creating a chamber that caused frequencies to resonate at 18.9 Hertz. Unlike Ghost Hunters, engineers actually find what they are looking for, but no one would watch a show that solves the mystery after one episode.

I pride myself on considering new ideas and challenging my preconceptions. When I first heard that race was social construct, it contradicted what I thought I knew and what I considered to be reasonable, perhaps even obvious. But setting that bias aside and considering the science and evidence, my position changed. And it will change back if a better case is made for race realism. I have, in fact, read three essays that purported to make the case for race being a biologic reality. But they were skimpy on the science and failed to even identify the races, so my position for now is that race is a social construct. Similarly, while praising the Scientific Method and peer review, I have included in my blog an overview of the shortcomings and potential for manipulation contained within them. My primary interest is finding and promoting the truth.

So while the infrasound explanation is attractive to a skeptic, I must point out that not all studies have reached this conclusion. One example of this was a double blind study conducted by Dr. Richard Wiseman and associates. For the study, actor Todd Robbins read a story about a professor who had been murdered in the hotel room the volunteers had assembled in. All the while, low frequency sounds were pumped in (or not, depending on which group it was). The results showed no statistically significant difference in responses between the group that was exposed to infrasound and the group that was not. Nor was there any difference in the reactions of self-described skeptics and self-described believers.

For now, there have not been enough studies conducted on this issue to reach a sound conclusion. The Wiseman experiment may prove to be an outlier, or it may be part of metadata that refutes the infrasound-instead-of-poltergeist hypothesis. In science, nothing is ever proven, we can only add to the body of evidence that suggests one outcome is the most likely one. The feelings of dread may come from infrasound, they may come from ghosts, but whatever the source, we’ll keep searching for it, and that is good science.