The very opposite was happening in parts of West Germany, most notably, in the experimental Kommunes of West Berlin. There, New Left activists—eager to test the bounds between private and public spheres—came together for a heady experiment in cooperative living. In the Kommunes, sex was uninhibited and revolutionary, lovers’ quarrels were resolved communally, nuclear families were outmoded, and “coercive toilet-training” was broadly decried.

When the Wall came down, Soviet daycares were closed. But was it too late? Had authoritarian toilet training tactics already wreaked psychological havoc? In 1999, 10 years after reunification, communist potty training made headlines anew—when German criminologist Christian Pfeiffer argued that the practice had rendered East German adults unsuited to democracy. Communal toilet training, Pfeiffer argued, broke a child’s naturally rebellious spirit and “raped” his soul. As a result, an adult exposed to the technique became authoritarian in esprit, and more likely to commit racially motivated crimes.

The personal is political, they say. Little is more personal than bowel relief—and little is more political than how you choose to raise your kid. It should be no great surprise, then, that at various points in modern history, potty training has been imbued with great ideological significance. Even today, the potty proves an enduring battleground on which grand forces—nature and nurture, state and individual—face off. Toilet training continues to be a source of profound anxiety—if not quite in the way that Freud theorized.

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In some instances, potty training assumes a symbolic form. Such is the case right now in Hong Kong, where a potty training-related fracas has escalated into a nasty altercation between the city-state and Mainland China.

Last month, a young Chinese child urinated on a public street in Hong Kong. In much of China, some parents let babies relieve themselves on city streets; but in Hong Kong, they don’t. This particular incident was filmed by a Hong Kong resident who controversially released the footage online. It went viral, and the incident inspired weeks of demonstrations and counter-demonstrations in both countries. But it wasn’t the solitary issue of public urination that fed such passions; rather, as The New York Times explained, the incident became a proxy for a larger cultural battle—over whether “Hong Kong, a former British colony [is] now being colonized by mainland China, whose visitors increasingly flood the territory with their money and alien manners.”

At other times, potty training is seen not just as indicative of broader social philosophy, but as an essentially formative episode in its own rite. This line of thinking took off during World War II.

American anthropologists turned to potty training in the early 1940s, while studying what they believed to be the particular aggressiveness of Japanese soldiers. Could this aggression, asked noted scholars like Margaret Mead, be caused by premature toilet training? Anthropologist Geoffrey Gorer thought so. He argued (as it turns out, falsely) that Japanese parents potty train their babies earlier than Western parents do—and that this accounted for “the overwhelming brutality and sadism of the Japanese at war.” Gorer’s reasoning was that premature toilet training forced Japanese babies to control their sphincters before important muscular development had taken place. This caused intense rage, which the infants soon repressed. This repression, in turn, gave rise to severe and compulsive personalities.