What makes running through an elaborately staged haunted house scary? The simulated gore, the jump-scares, and the grisly imagery do most of the work on your blood pressure, but there’s nothing quite like exploring a spooky old house yourself. Just imagine it: the floorboards creak as you push open a dilapidated door; a corner of the room you’re standing suddenly goes ice cold. A photo you take in the dark shows a blurry, human-like figure. The scariest thing you could do this Halloween is find and prove that ghosts are haunting a house. Here’s how you would do it.

According to a poll conducted by the Associated Press, around 34 percent of the U.S. population believes in ghosts, and Gallup found a similar percentage believes that houses can be haunted. Popular shows like Syfy’s Ghost Hunters capitalize on these numbers, encouraging many amateurs to investigate. So far, nothing has come of it. Doing it right means coming at ghost hunting like a scientist, starting with your approach.

Before You Hunt

While ghosts are by definition beyond the natural world, the best method we have for exploring the real world around us (so far) is the scientific method. Generally, being scientific means being objective, diligently recording observations, and controlling interfering variables. For ghost hunting, this means you shouldn’t assume ghosts inhabit a house before you investigate. That’s for the data to decide. No matter how many reports of ethereal figures or weird sounds or floating chairs you hear, your data is the determining factor. Don’t let a disturbing history lead you down the wrong path.

Not everyone can be a ghost hunter. Sure, the Ghost Hunters themselves are plumbers, but that doesn’t mean plumbers make good investigators. First familiarize yourself with proper observation techniques, the equipment you will need, and the methods of objective data collection.

Next, know that your body is always lying to you. For example, we are terrible at recognizing the temperature changes that are so often attributed to spirits. Prove this to yourself by finding a bathroom and touching your hand to the ceramic tile. Then touch some carpet in the same building. The ceramic feels “colder,” right? Though it might feel that way, both the carpet and the tile are the same temperature, room temperature. Your hand is actually feeling the heat in your hand flowing more easily into the tile than into the carpet, not a measurable temperature. Similarly, finding a cold spot in a creepy house doesn’t mean a whole lot. Your eyes and ears can play tricks on you too.

Since there isn’t any repeatable, established evidence of ghosts so far, be ready with alternative explanations for any weird things you may encounter. For example, in 1972, the famous paranormal investigator Joe Nickell’s had his first case. He was examining reports of mysterious footsteps, piano music, and apparitions in an old inn called Mackenzie House in Ontario, Canda. The caretaker of the inn was positive that it all added up to a haunting. However, after interviewing all the employees of the inn, Nickell discovered that it shared a wall with another building, one that had nighttime cleaning crews running up and down a parallel staircase and a resident who frequently played piano. As for the Mackenzie House’s caretaker, her visions of apparitions fell in line with the disturbing experience of sleep paralysis.

Even figures or “orbs” in something more substantial like a photograph can be dust or insects reflecting camera flash, “voices” can be random static, and cold spots in a house can be attributed to poor ventilation. Remember Carl Sagan: “Extraordinary claims require extraordinary evidence.” Always try to pass that test.

So now you’re ready to find some ghosts. Time to suit up. But you won’t need a proton pack…you won’t need much at all.

Gathering the Evidence

Popular TV shows and amateur investigators make ghost hunting look like a technically complicated affair. They bring everything from electromagnetic field (EMF) meters to infrared thermometers to microphones to camera traps for an investigation. Though it seems like the scientific thing to do, these tools won’t do you any good. Sure, EMF meters will pick up electromagnetic fields and microphones will pick up sounds you may not hear, but this data has never been linked to ghosts conclusively. A barometer, for example, measures air pressure, or heavy the atmosphere is. This is a known quantity. Ghosts, on the other hand, have no known quantities, so no matter what a thermometer or EMF meter finds it is not, by definition, measuring a ghost.

Some of these instruments have potential pitfalls as well. Infrared thermometers can pick up heat signatures of a ghost hunter herself – standing in one location or near a wall for too long can produce “mysterious” footprints or human figures. Electromagnetic fields – emanating from wi-fi, radio towers, and cell phone calls — pervade seemingly every square foot of every industrialized country, making those meters unreliable at best as useless at worst.

And turn on the dang lights while investigating! There’s no reason to introduce the oddities of the dark while looking for evidence.

All you’ll really need is a notebook to record everything you find, a camera to photograph any physical evidence, and maybe a tape recorder to conduct interviews with witnesses. Control as many variables as you can (e.g., observe a supposedly haunted room during different times of the day over several weeks, not just when events occur or during one night), focus on what you actually find and not a creepy or even criminal house history, and don’t go into a house expecting to prove a report. As Sherlock Holmes said, “It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.”

If there really are ghosts out there – an estimated 110 billion humans have died so far on this planet, so there would be plenty – using these techniques should help you find them. You’d be the first. Happy hunting!

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Image: The Pico House by Grendl

Kyle Hill is the science editor at Nerdist Industries. Follow on Twitter @Sci_Phile.