A little known fact about me: I love ghost hunting shows. There's something about the unknown and maybe finding proof that there is life beyond death that appeals. I'm someone who need answers. I want to know what makes something tick, to dissect the working. So when I watch these ghost hunting shows, I'm always a bit intrigued by the various pieces of "evidence". I'll admit, most of the time, watching those shows, I'm left feeling disappointed because I expect MORE to come from it. Silly of course, but I want a more clear defined...yes there is or no there isn't.
However, sometimes there ARE scientific explanations for what's going on. It's pretty easy to conclude first off that a place that is 'haunted' is going to have more witnesses, more people who say something's going on. It's the lemming effect. If something happens that you can't explain and you've heard stories that something's not quite right, well then you're going to start to believe it and you're going to follow suite and say that what you experienced was paranormal.
Ever wake up unable to move? You might want to say that a ghost is holding you down or whatever, but there are other explanations for this paralysis that doesn't have to be paranormal such as sleep paralysis or hynagogic trance. It's said that most people experience a hypnagogic trance once or twice in their lives, although it is far more common in people with epilepsy or suffer from certain sleep disorders.
Most of the time, however, those who claim to have a ghostly encounter were awake. So then we have to look to other explanations. Some paranormal investigators think that the presence of stronger than normal electronic magnetic fields (EM fields) may be an indication of something supernatural. These fields may come from electronic equipment or geological formations. You'll often see investigators carrying around an EM reader. The first step when finding stronger than normal readings would be to make sure that what you're reading isn't coming from something electronic. Researchers believe that these EM fields can interact with the brain, causing hallucinations, dizziness or other neurological symptoms. They theorize that this is one of the reasons people report more ghostly activity at night, because of the way solar wind interacts with the Earth's magnetosphere. Electrical stimulation, for instance, to the angular gyrus of the brain can cause the sensation of someone behind you mimicking your movements. In other parts of the brain, it can cause people to hallucinate or have near death experiences.
All right but if it's just an effect on the brain, what about the cold spots? Those are physical symptoms. Cold spots are a common phenomenon in buildings believed to be haunted. Usually it's described as sudden drops in temperature or localized cold areas in an otherwise warm room, thought to be from the ghost drawing the energy out of the room. Often, however, these can be traced back to specific sources such as a drafty window or a chimney.
There may be one other thing playing tricks on you. Infrasound (an extremely low frequency between .1 -20Hz). At these levels, humans can't hear it, but we can FEEL it. It's believed that a good portion of the population is thought to be hypersensitive to these low frequencies-- causing nausea, extreme fear or awe, anxiety and chills. Researchers also believe it can affect vision by causing vibrations of the eye, making you 'see' things. Infrasound can be produced by storms, strong seasonal winds, weather patterns and some earthquakes.
In 1998, the Journal of the Society for Psychical Research published a paper called ‘The Ghost in the Machine’ by Vic Tandy. It described Tandy’s experiences with infrasound in his lab. While doing some experiments, his coworkers complained of various unknown 'spooky' feelings and chills in his lab. One woman even was said to have seen something. While working late at night, Tandy claimed to have had the feeling of being watched and catching the figure of something at the edge of his vision, but when he turned, there was nothing. When he brought in a fencing foil to repair, it started to vibrate. As he moved the blade around the room, it began to vibrate more strongly in the centre of the lab and at the edge of the room, stopped. He discovered that there was a 19Hz standing wave in his lab and that the walls had caused the sound waves to double back on itself, producing an area with enough energy to vibrate the blade. The source of this wave was a newly installed fan. When turned off, all phenomena associated with it stopped.
There are many natural reasons for paranormal activity if you know about it and where to look. What others can you think of?