Spine-tingling chills, haunted houses, vampires and werewolves -- exploring the science behind scary stuff, and debunking some myths.
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Why do we get a chill down our spine when we watch a horror movie? Is there such a thing as a haunted house? A werewolf? Why are black cats considered bad luck?
Award-winning astronomer Stephen James O'Meara, answers these and other questions in the book "Are You Afraid Yet: The Science Behind the Scary Stuff."
When we watch a horror movie or hear a scary story, we typically have very physical reactions, even though we know the events are fiction.
O'Meara says there are neurons that fire up when we see something that relates to something else that has made us afraid in the past. This works in conjunction with what O'Meara calls the "terror center" of the brain, the amygdala, which alerts us to fear.
And physically, things begin to happen in our bodies. Our hearts start pumping more blood -- from about a gallon a minute, to five times that.
"What happens is our brains prepare our bodies for fight or flee," said O'Meara. "Your lungs expand to bring more air, in case you have to run. Our eyes dilate so that we're more sensitive, our ears is peaked."
He adds that there's also the "very primitive" reflex where the tiny muscles attached to our hair tighten, making us feel as if our hair is standing up.
O'Meara also covers some scary myths in his book -- from black cats to vampires. He says the idea of vampires may have come from a rare blood disease.
"Porphyria -- it's a fascinating disease, and it's one where people who are exposed to sunlight, so they're photo-sensitive, it can actually cause their skin to boil and blister, so they only go out at night. Not only that, but it turns their teeth gray so it looks like they've been biting somebody's neck and their urine gray, so it looks like they've been drinking blood."
Still other illnesses may have led to the myth of werewolves. "Essentially there are two types: There's lycanthropy and hypertrichosis. Lycanthropy is a split-personality disorder, and it just means that the person may act out like a wolf and may even run around chasing animals and eat them. As opposed to hypertrichosis, which is an actual genetic disorder where hair covers the entire body."
As for haunted houses, O'Meara says scientific studies have shown that there are fluctuations in electromagnetic wave patterns around certain houses. He says the fluctuations can be caused by underground minerals or even solar activity.
But these fluctuations can cause people to feel as if there's a presence.
"Your temporal lobe may be sensitive enough to pick up these faint vibrations -- you're not mentally aware of it -- but these vibrations can actually cause you to feel the presence of someone around you, and they may also create hallucinations, depending on the strength of the field."
O'Meara says his book brings to light cases of scientific investigation that may explain some of the phenomenon, but there's still a lot that can't be explained.
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