In February 1985, a 29-year-old woman from Suginami, Tokyo, sent a short letter into a magazine about an experience she'd been having a lot. It would spark a slew of others reporting the same phenomenon, which would eventually be named after her.
"I'm not sure why," Mariko Aoki wrote. "But since about two or three years ago, whenever I go to a bookstore I am struck by an urge to move my bowels."
Look, there are a lot more pressing issues out there we realize. We should probably deal with the whole COVID-19 and cancer situation before we move onto desperately needing a poo while looking for a copy of 50 Shades of Grey. But it is an interesting one nonetheless, largely due to the sheer number of theories people have come up with to explain it – or find out whether it even really exists.
The odd phenomenon turned out to be fairly widespread, with many people writing in to the magazine to say that they had the "condition" too. People describe it as the overwhelming, sudden and unbearable urge to defecate, felt only in book stores. For some reason, libraries just won't make you want to drop a deuce.
Some have claimed to have had other symptoms, such as a pain in the gut and "a kind of heaving sensation in the rectal passage". Some say it is so debilitating that they have to get others to go book shopping for them.
So, what could be causing it? Well, there are several suggestions, though really none of them are conclusive. Some have claimed that it could be caused by chemicals within the ink of books that brought on defecation. As you'd imagine, there isn't exactly a rush to cure this condition, so not much research has been conducted on it. However, a Japanese TV show The Real Side of Un'nan attempted to get people to poop by using the smell of ink, with no success at all. Furthermore, we'd probably know a bit more about the condition if the staff in book stores constantly needed a poo.
Others have suggested that it could be down to association, in a sort of reverse Pavlov's dogs situation. Just as the bell made Pavlov's dogs salivate through the association with food, in this hypothesis, the books make people want to defecate through the association with reading books while you take a poop. Again, this would not account for why people don't need to go while in libraries, nor constantly while near the bookshelf at home.
Another popular explanation is that it's to do with posture when you bend down to pick up books, and the inevitable effect on the rectum (see the main image).
Of course, one explanation is that there is no such thing as Mariko Aoki syndrome at all, and it's merely a type of frequency bias. It's possible that as she drew attention to her own personal experience – perhaps she was conditioned in the Pavlovian way, who knows – and the story went around the world, people merely began to notice that they needed the toilet while they were in the store, seemingly confirming that the phenomenon is real.
Unless Penguin or Waterstones start pumping money into getting to the bottom of this (so to speak) we probably won't know for some time.