Samara is back in the new trailer for Rings, doing what she does best: Making people cough up long, wet ropes of hair. For many fans of the Ring franchise, watching a woman gag as she chokes and slowly tugs a thick cord of hair out of her throat is almost too much to bear. According to William Ian Miller, author of The Anatomy of Disgust, that revulsion is hardwired and reinforced by millennia of cultural beliefs. In no point in human history has hair ever belonged in someone’s mouth.

Psychologists consider disgust to be the emotion of self-protection: When we react to something with disgust, it’s highly likely that thing can somehow harm us. It’s thought that humans react with disgust to poop because it is a vector for bacteria and can make us sick. Hair, Miller argues, is not all that different, as he explained in his book by referring to an experiment in which infants, exposed to many classically revolting stimuli, were grossed out by hair before poop:

I suppose that like my children they know from prior experience that it is unpleasant to feel a hair in the mouth, and that once they acquire notions of contagion and pollution the sensation will come to elicit disgust as well. The issue, however, is more one of tactility than of taste, even if we recognize that tactility is an important aspect of palatability, if not quite of taste as narrowly conceived.

There must be something about hair that is inherently disgusting to us. In studies on cultural revulsion to women’s armpit hair, it’s been pointed out that body hair harbors bacteria, and so is more likely to smell bad if it is unwashed. Of course, bathing happens relatively frequently among modern humans, so having body hair is not really a problem, but it is possible that ancient humans made a connection between illness and the presence of hair — and therefore didn’t want it anywhere near their mouths. Similarly, pubic hair functions biologically as a sieve, trapping small, potentially harmful objects from entering the genital zone. It’s pretty clear why humans wouldn’t want its contents in their mouths.

Besides, hair can’t be digested by our stomachs, so it can’t be counted as a nutrition source. Humans with the disorder trichophagia, the compulsive eating of hair, end up having to undergo surgery to remove massive balls of hair called bezoars from their stomachs.

Our cultural disgust of hair most likely stemmed from our evolutionary revulsion. Hair, Miller points out, is now “mixed up with sexual desire,” grows in “comical” places like the nose and ears, and in “nefarious,” dark areas like the groin and armpits. While hair can be sexy on our heads or faces, our feelings get confusing when it ends up in our food.

Whether it's from the head or the crotch, hair is likely to carry a lot of dirt and bacteria.
Whether it's from the head or the crotch, hair is likely to carry a lot of dirt and bacteria.

“That it is long proves that it comes from the head and not from the groin, but that does not seem to lessen one whit its disgust-generating powers once it gets in your food or in our mouth,” Miller writes.

Fortunately, our chances for hair-induced disgust are now pretty slim. For present-day humans, the only situation in which you’re likely to get a clump of hair in your mouth is if you frequent restaurants with poor hygiene practices — or make the mistake of watching Samara’s infamous video.