It’s probably best to start with Hanks’s version and work our way backward. Hanks claims that some researchers realized that the phrase “bloodcurdling” might have some basis in fact, so they showed people a horror movie and tested their blood, discovering that people who watched horror movies had higher levels of a blood clotting factor. Therefore, Hanks said, “the particular brand of fright stemming from horror cinema” literally curdles the blood by making it clot.
In addition to adding no new insight into the story, this actually is not what the Dutch doctors who conducted the research concluded in their study.
You can read about the study yourself in the Guardian, but the thrust of it is that Dutch doctors Banne Nemeth and Luuk Scheres actually concluded that fear—not specifically horror movies—increases the blood clotting factor, perhaps due to the threat of injury that prompts fear in the real world. To that extent, horror movies are simply a mediated reflection of this real world issue. “We think that from an evolutionary perspective it is actually a good thing to clot a bit faster if you experience fear,” Nemeth told the Guardian. “Fearful situations often come together with trauma or injury. So from this evolutionary perspective it would be good to prepare your body for blood loss.”
That much is, of course, fine science as far as it goes. But the doctors’ began their research with a supposed fact that doesn’t actually support their research the way they claim it does. As the Guardian put it:
Banne Nemeth, who led the horror film study, said it originated from the fact that the idea of a bloodcurdling fright exists in several languages, including Dutch (bloedstollend), German (das Blut in den Adern erstarren lassen) and French (à vous glacer le sang).
We can start knocking out some of the claims pretty easily. The French phrase does not carry the same meaning as its English equivalent. The French term refers to blood freezing or chilling, since the word glacer means to “make into ice.” This would be closer to the English expression “blood-chilling.” Similarly, the German phrase exactly parallels the French and literally means “let the blood freeze in your veins.” Both of these phrases hark back to the idea that fear causes feelings of coldness or chills, often attributed to the constriction of capillary blood vessels during states of fear to increase blood pressure. It’s a widely known effect and a seemingly sufficient explanation for the phrase.
The Dutch term, so far as I know, means the same as the English, or most literally, “blood solidifying” or “blood coagulating.”
Here I must confess that I am at a disadvantage; since I do not speak Dutch, I am unaware of how old the term is in the Dutch language in order to determine whether the term spread from English to Dutch or Dutch to English. However, I can tell you that according to standard dictionaries, the compound English term was first used in 1724, so it is not a particularly ancient term. (I can trace the Dutch word back to the late 1700s, but it clearly was already in use by then.) The Online Etymological Dictionary suggests a more recent origin, tracing the specific term bloodcurdling to 1817, but from an earlier figurative use of the word “curdle” to refer to blood in the presence of fear from around 1600. The assumption—granted this cannot be proved—is that the phrase emerged from the earlier concept chilling or freezing the blood by describing the solidification of blood upon becoming (figuratively) ice. Thus, the English phrase is a somewhat imprecise rendering of the French phrase that just happened to suggest to modern researchers the concept of clotting, which was not really the intent. According to standard dictionaries, the English phrase “blood chilling” dates back to 1632, from an earlier use of “chill” in reference to blood, presumably making it the earlier version, or at least coeval in translating the presumably older Continental phrase, which was already an entry in the dictionary of the Académie française in the 1600s. Compare to the better-known phrase “to make one’s blood run cold.”
Because the Dutch researchers discounted or removed entirely the implication of freezing and chilling from their exploration of blood-chilling language, they were able to shift the meaning of the phrase toward clotting to create a presumably spurious linguistic support for their findings about blood clotting and fear. There is, I suppose, the possibility that the word “bloodcurdling” might have been meant to suggest clotting, though the researchers would need much more evidence to explain how and why that came about given the evidence in favor of an icier explanation.
And that, Micah Hanks, is an example of how you add value to a recap of an article rather than subtract value from it: by offering something that is not already in the original.