“Bloodcurdling” is a phrase tagged to many horror movies. This is along with “heart-racing”, “skin-crawling” and “tooth-chattering.” With the former it seems that this isn’t simply something dreamed-up by advertising executives. Moreover, according to The Guardian, “bloodcurdling” is not just an English language notion. Bloodcurdling due to fright is found in Dutch (bloedstollend), German (das Blut in den Adern erstarren lassen) and French (à vous glacer le sang).
A study, conducted by Banne Nemeth, of the Department of Clinical Epidemiology, Leiden University Medical Center in the Netherlands, and colleagues, has found frightening movies “are associated with an increase of blood coagulant factor VIII without actual thrombin formation in young and healthy adults.” Factor VIII is a blood-clotting protein. In most people (excluding those with specific types of hemophilia), triggers blood to clot when a cut occurs. The mechanism stops someone from bleeding heavily and losing a dangerous amount of blood.
For the study, researchers recruited 24 healthy volunteers aged under 30 years. Fourteen were asked to watch a frightening (horror) movie followed by an educational movie. The other 10 subjects watched the movies in reverse order. The movies were viewed a week apart, on the same time of day. Both movies had a running time of around 90 minutes.
At the end of the sessions, the researchers took blood samples. With these, they were looking for markers, or so-called “fear factors,” represented by blood coagulation activity (activity of the clotting factor VIII). They also asked the subjects to rate the fear experienced during each movie using a scale.
With the results, unsurprisingly the horror movie was perceived as more frightening than the educational movie. The difference in factor VIII levels before and after watching the movies was also higher for the horror movie than for the educational movie. Thus the conclusion: scary movies can be bloodcurdling.
The research is published in the British Medical Journal and is titled “Bloodcurdling movies and measures of coagulation: Fear Factor crossover trial.”
