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A Science Based Ghost Hunting Toolkit

Donate How a TV ghost hunting show might look if they did what they claim, and used science.  

by Brian Dunning

Filed under General Science, Paranormal

Skeptoid Podcast #668
March 26, 2019
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A Science Based Ghost Hunting Toolkit

I don't want to make you feel old, but believe it or not, it's been more than 11 years since the Skeptoid episode on "Ghost Hunting Tools of the Trade" in which we looked at the electronic gadgetry used by television ghost hunters. Back then, when there were so many copycat ghost hunting shows on the TV networks that bill themselves as science channels, it was almost like an arms race to see who could bring the fanciest, most expensive-looking gear into the supposedly haunted locations. Some even went so far over the top as to have guys outside in vans set up with TV monitors to look they were on a Mission Impossible spy operation. It got so far past the point of absurdity that it became a parody of itself. So today we're going to look at how this might be done better: what a ghost hunting toolkit might look like that's based on science, rather than on TV ratings.

To do this, we're first going to define what we mean by a science-based toolkit. Science is the systematic study of the structure and behavior of the physical and natural world through observation and experiment. The scientific method is the process of finding a replicable observation, then testing hypotheses to form a theory that explains the observation. This presents ghost hunters with the first roadblock: there has never been a replicable observation of the phenomenon that they use the term ghost to encompass. In plainer language, we've never caught a ghost or had one that we could study. Ghosts have no properties. Ghosts have no describable characteristics.

If we catch a dog, we can measure it and learn all kinds of things about it. We can use fancy electronic equipment, like cameras and temperature sensors, to record its physical properties. Other people can come up, make similar measurements, and get the same answers. This is what we mean by a replicable observation. Then, when someone else finds an animal and catches it, they can compare their own measurements to the ones on record, and thus determine that what they have is a dog as well. Dogs are proven to exist, and have established properties.

This is an obvious problem for ghost hunters. They're out there looking for something that has never been proven to exist, and thus does not have even a single established property. If you don't know what you're looking for, how can you select the right detection tool? A blind man is not going to find a cloud by poking around with his cane; how is a ghost hunter going to find something without any information telling him what type of tool he needs? And yet, ever since TV ghost hunting became a thing, this is what they've been doing, and the unsurprising result is that they've never found a ghost. The reason is that their methodology has been unscientific from the beginning; they failed to take even the first, most basic step of having an observation.

So let us now put down our torch for burning, and pick up our hammer for building. Let us now devise a science-based toolkit for ghost hunting.

The fact is that many people believe in ghosts, and ghost hunting is going to continue no matter how much pragmatism and Socratic deconstruction we throw at it. And we should presume that people whose intent is genuine wish to go about this in the best possible way. We should not take the position that the entire exercise is pointless, because it isn't. If a search is conducted scientifically, it is more likely to find something that's real — even if that something turns out to be a mundane physical cause, like something mechanical or natural in the building or possibly even a hoaxer. These things all have established, detectable properties, so a science-based ghost hunt will make every effort to find these. If an air vent is making a bumping noise, no responsible ghost hunter wants to arrive at the wrong explanation of calling that a ghost.

Example: There's a cold spot in a room. Ghost hunters find it by detecting cold patches on the wall with an infrared thermometer or a FLIR camera. Since those tools are not equipped to find the causes of a cold spot in the room, they find none, and call it a ghost. A science-based toolkit would include a can of spray smoke, which is one easy way to detect a draft — the most common cause of a cold spot — coming perhaps from something like a bad door seal.

I spoke with two friends who often accompany local ghost hunters on investigations, Ben Radford and Kenny Biddle. Both have friendly relationships with the ghost hunters and are open about their skepticism. Both gave me the same answer to my very first question, which was what things they bring on a ghost hunt. Their quite rational answer: "It depends what the claim is."

This is an important point. TV ghost hunters show up at every destination with the same set of gear: a digital audio recorder which they immediately use to start listening for electronic voice phenomena; a FLIR camera to look for thermal anomalies; night mode video cameras to look for physical apparitions; and usually a self-described psychic to try and make contact. Doesn't matter what the report is; this is how they show up, and it's usually the extent of what they do. From this, we can infer that they believe they already know what to look for and how to detect it. Their history of never collecting evidence of a ghost indicates it might be time for a rethink.

Here is a partial list of some of the types of claims made, and what tools to bring for each:

1. Mysterious noises

When a homeowner reports mysterious noises, the cause often ends up being pests like rodents or birds, defective plumbing, or noisy neighbors. While traditional TV ghost hunters might waste time listening for EVPs or trying to commune with the dead, science-based ghost hunters are more likely to hire an exterminator experienced at looking for the signs of an unseen infestation, a plumber familiar with noise issues, or just a friendly knock on the neighbor's door to correlate neighbor voices with perceived ghost voices.

2. Mysterious images on video

Lately, some TV ghost hunters have turned to a device called an SLS, for Structured Light Sensor, to visually spot ghosts in dark rooms. Although a Structured Light Sensor is a real thing — it's a projector and camera used to make 3D scans of objects — what the ghost hunters are using is simply a Microsoft Xbox Kinect video game controller, sometimes repackaged in a different case. The actual purpose of a Kinect game controller is to look at you, the person playing the video game, and determine how you're standing or posing or moving. To do this, the software attempts to superimpose a stick figure on whatever it sees. It's usually pretty good at matching your body position. But when you point it at something that's not a human, it struggles to find a basic stick figure form, but it still draws one, matching whatever object it sees as best it can. On the TV shows, they point it at an empty room, and hope that the superimposed stick figure will trick the viewer into thinking the Kinect is actually seeing a humanlike form which they hope you'll interpret as a ghost.

This is doing science backwards. It's not seeking to explain a mysterious image, it is creating a image — and one that's not even mysterious to anyone who understands a Kinect.

Ben and Kenny have both found the most common cause of a mysterious image captured on security video is insects on or near the lens. They're out of focus and blurry and thus mostly transparent, they move around, and can appear pretty compelling. A science-based ghost hunting toolkit for these cases may include things like a ladder or pole for reaching the camera, or perhaps a bag of purchased insects.

3. Apparitions

Often when the report is of visual phenomena, the cause turns out to be reflections, and car headlights are a disproportionately common cause. Traditional ghost hunters might point a FLIR camera around the room looking for the ghost, but a science-based toolkit would be things like a spotlight, a laser pointer, a car outside, and radios for communication. There are an infinite number of possible light sources and reflective surfaces, so a cursory examination might suggest other useful tools. In addition, it's often handy to take photographs of everyone present, as it sometimes turns out that a person who was there ends up being mistaken for a ghost in some blurry photograph.

Based on other reports, Ben and Kenny have brought other things including carpenter's levels that can explain why cabinet doors open themselves, spray smoke to find drafts of air from open windows or hidden leaks, or electricians and structural engineers familiar with weird things a house or building might do. In addition, modern devices like the Tile, used to find misplaced keys, have reduced the number of cases of ghosts apparently hiding keys and other small objects that the owner knows he didn't misplace.

Finally, every toolkit must allow for the ability to catch hoaxers. Although actual hoaxing is rare in real-world ghost hunts, it's commonplace on the TV shows because the producers know they need to have something to point their cameras at to make a show. Ben and Kenny have both encountered this. Handy tools for catching hoaxers include powder, such as flour, to lightly sprinkle on any floor where you suspect a hoaxer might try to go undetected to do things like fiddle with lights or cameras or throw something or make some noise. In one case where electronic equipment was suspected of being switched on and off, Kenny brought a bug detector to catch any RF remotes that someone might have been using. Hoaxers sometimes do this because signals from the more common IR remotes can be seen with ordinary video cameras.

Although it seems like TV ghost hunters would be the ones most likely to use ostentatious electronic gadgetry because it makes exciting, sciencey-looking programming, it's not true. Real-world, honest, believing ghost hunters use these same tools, according to both Ben and Kenny. Perhaps it's a tribute to the advertising effectiveness of product placement on the TV shows, but real-world ghost hunters do still use fancy gadgets. Popular ones include not only the Kinect Structured Light Sensor, but also the K2 Meter, which is an inexpensive EMF detector that has colorful display lights; the Mel Meter, which is a combination temperature sensor and EMF meter marketed and sold specifically to ghost hunters; and the Spirit Box, based on Frank's Box discussed in Skeptoid #429, and which rapidly sweeps through radio stations in the hope that you'll hear something that sounds intelligible and believe it to be a ghost. But as we can tell from this whole discussion, all of these gadgets are doing science exactly backwards. These devices are all designed to create some anomaly, not to identify the source of an existing one. They are there to satiate the appetite of ghost hunters for some strange experience; they do nothing to locate the cause of a mysterious experience reported by some frightened resident.

And there we have it: a science-based ghost hunting toolkit. It won't necessarily produce the ghost proof you're hoping for, but it's far more likely to find the true cause of the report.

By Brian Dunning

Please contact us with any corrections or feedback.


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Cite this article:
Dunning, B. "A Science Based Ghost Hunting Toolkit." Skeptoid Podcast. Skeptoid Media, 26 Mar 2019. Web. 15 Apr 2021. <>


References & Further Reading

Bader, C. Paranormal America: Ghost encounters, UFO sightings, Bigfoot hunts, and other curiosities in religion and culture. New York: New York University Press, 2017.

Biddle, K. "Challenging Claims of Electronic Voice Phenomena (EVP)." A Closer Look. Committee for Skeptical Inquiry, 17 Sep. 2018. Web. 21 Mar. 2019. <>

Hill, S. Scientifical Americans: The Culture of Amateur Paranormal. Jefferson: McFarland & Company, 2018.

Long, K. "7 Ghost-Hunting Tools Recommended by Paranormal Investigators." Technology. Mental Floss, 26 Oct. 2018. Web. 21 Mar. 2019. <>

Nickell, J. "Scientific Investigation vs. Ghost Hunters." Investigative Files. Committee for Skeptical Inquiry, 1 Sep. 2010. Web. 21 Mar. 2019. <>

Radford, B. Investigating Ghosts: The Scientific Search for Spirits. Albuquerque: Rhombus Publishing Company, 2017.


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