The Mariko Aoki phenomenon is a Japanese expression referring to an urge to defecate that is suddenly felt after entering bookstores. The phenomenon’s name derives from the name of the woman who mentioned the phenomenon in a magazine article in 1985.
According to Japanese social psychologist Shozo Shibuya, the specific causes that trigger a defecation urge in bookstores are not yet clearly understood, and it is sometimes discussed as one type of urban myth or a mild form of mass psychogenic illness.
The term receives its name from Mariko Aoki, an otherwise little-known Japanese woman who contributed an essay in 1985 to the magazine ‘Hon no Zasshi’ (which means ‘Book Magazine’). In that essay, she related how she came to the realization that for some years, walking around a bookstore inevitably made her want to go to the restroom. The editors of the magazine received reports of other readers who had similar experiences, and named it the ‘Mariko Aoki phenomenon.’
Possible theories behind the phenomena include the smell of paper or ink having a laxative effect, the association with reading on the toilet at home, and the posture of browsing making bowel movement easier. The evidence for these explanations however remains weak. The psychological hypothesis that the effect arises from feelings of nervous tension in the face of all the information represented on the bookshelves is well supported by literary figures.
One known mention in Japan dating back many decades regarding a relationship between bookstores and the defecation urge is in Jun’nosuke Yoshiyuki’s ‘Amidst the Hustle and Bustle’ (1957), and similar mentions can be found in works by Jo Toyama (in 1972’s ‘The Emperor and the Lieutenant’) or Shoichi Nejime (in 1981’s ‘Words, Too, Can Sweat—Literally’). It was raised in the media from as early as the 1980s. For example, the magazine ‘Common Man Weekly’ (1984) records television newscaster Tetsuo Suda talking about a similar experience. Also, the radio program ‘Young Paradise’ (on Nippon Broadcasting System from 1983 to 1990) had a corner for sharing bowel movement related episodes, and one time the defecation urge felt in bookstores was discussed by being referred to as the ‘Yoshiko Yamada syndrome.’
From the year 2000 onward as the Internet grew, the Mariko Aoki phenomenon came to be even more widely known. In 2002, an Internet search using the keywords ‘bookstore, defecation urge’ produced links to dozens of websites discussing the phenomenon.
Persons with a history of experiencing the Mariko Aoki phenomenon were described as having a “book bowel” tendency by ‘Book Magazine.’ According to one very small-scale study, while the fact that people with a book bowel tendency existed throughout all of Japan indicated a lack of any regional difference, a female bias was observed with a male to female ratio of between 1:4 to 1:2. It has also been posited that the tendency is uncommon in so-called ‘sporty males.’ One report has estimated the prevalence as being between 1 in 10 to 1 in 20 people. Psychiatrist Takashi Sumioka noted the possibility that hidden behind the symptom of ‘wanting to go to the bathroom’ may be a condition such as irritable bowel syndrome or anxiety disorder.
One opinion is that ‘it often happens when reading serious books such as literary works.’ The novelist Jiro Asada has said that the strength of the symptoms are proportionally related to the size of the bookstore and the degree of difficulty of the books he is looking for. Another person who used to be struck by a defecation urge whenever going to a bookstore reported that the symptoms suddenly resolved themselves immediately upon starting a part-time job at a bookstore. A hypothesis had existed for a long time that some chemical substances contained in the paper or ink of books emit a smell that induces the defecation urge by way of acute sensory stimulation, but it was never confirmed.
In response to a request for an interview by the editorial team of ‘Book Magazine’ in 1985, the psychiatrist Masao Nakazawa attempted to explain the set of symptoms by using the term ‘hyperresponsiveness.’ In hyperresponsive reactions to stress, the sympathetic nerves take precedence, ordinarily leading to a constipative tendency. However, it is considered possible, in special circumstances—for example, when shown a glass of cold milk—for the gut to experiencing a loosening by way of a type of conditioned response mechanism. Nakazawa suggested that a similar mechanism could be involved in the Mariko Aoki phenomenon.
Another well-known theory is that which states that a person entering a bookstore may feel psychological stress from worrying about what to do if they need to go to the toilet but there isn’t one in the store, and that this has the unfortunate effect of focusing the person’s conscious thoughts on bowel movements. In psychiatry, this type of mental stress is called ‘anticipatory anxiety,’ and it is a characteristic symptom of panic disorder and other anxiety disorders. There is also the converse opinion: that bookstores have a relaxation effect that stimulates bowel movements. In the stressful life of modern-day society, many people experience interrupted bowel habits and the constipation that this causes.
Essayist Mariko Ishibashi stated in a 1995 essay that the defecation urge is induced by the nervous tension generated when a ‘flood of information’ pours into one’s field of vision. The posture or gaze of a person while they browse-read a book while standing is often focused on as a contributory cause of the defecation urge. This is based on an interpretive model in which a defecation urge arises due to focusing one’s gaze on a single point while adopting an upright or a slightly head-down posture. It has also been suggested that upright reading while also carrying or shouldering baggage could put force on the abdominal muscles and stimulate a defecation urge.
The Daily Omnivore 