"Boo!" Anyone can scare an unsuspecting person with a single word spoken loudly, but that's quite a bit different than creating a sustained, scary atmosphere in a feature-length motion picture that keeps viewers on edge for the entire running time.

A good horror movie leaves a lasting impression; we might remember that Psycho made us scared of showers, or that Jaws made us think it wasn't safe to go in the water, or that A Nightmare on Elm Street made us afraid to go to sleep. We might talk about fright flicks that made our stomach clench or made us gasp or gave us goose bumps. But can it be said that horror movies are literally bloodcurdling?

Science now says "yes."

According to a new study by doctors and academics at a university in the Netherlands, reported on by The Guardian, volunteers who sat through a horror movie had "higher levels of the blood-clotting protein factor VIII" than those who watched a documentary about the wine industry in France.

Clotting, of course, is a synonym for curdling, and so it can be truthfully stated that horror movies are bloodcurdling. To reinforce that conclusion, take a few minutes and watch the trailers for the two movies shown to the study participants, about a week apart.

First, Insidious (2010), directed by James Wan and starring Patrick Wilson and Rose Byrne. It was selected by the researchers "because it is consistently scary rather than building up to a climax."


Next, A Year in Champagne (2014), a documentary by David Kennard about the famed wine region of Champagne in France. The only potentially scary moment in the trailer comes when a cork is popped.


Now, which movie do you think will make your blood curdle? Keep that in mind the next time you're deciding what to watch at a theater or at home!