CERTAIN kinds of property crimes are up sharply in Germany, as I explain in this week’s print issue. But in many ways the more interesting trend is the ongoing decline in violent crime in Germany, Europe and much of the developed world. Criminologists have for years been puzzled by this phenomenon, with theories ranging from decreasing numbers of lead poisoning to better policing. But one of the most intriguing theories, and one with vast implications for America in particular, comes from Christian Pfeiffer, the director of the Criminological Research Institute of Lower Saxony in Hanover. Mr Pfeiffer has found a correlation between declining rates of children being spanked (or otherwise punished physically) and subsequent decreases in violent crime. In Germany, for example, it used to be common until well into the last century to discipline kids in this way. Not doing so almost amounted to being negligent. But then parents and teachers gradually stopped beating children.

When Mr Pfeiffer’s team polled adult Germans in 1992, 26% answered that they had been raised without any physical punishment at all. In the latest poll, soon to be released, that ratio has gone up to two thirds.

People who as children experienced the “powerlessness” of frequent spankings report a disproportionately greater interest later in life to own guns, Mr Pfeiffer says. They also demand more draconian prison sentences, including the death penalty, for convicted criminals. And they seem more prone to violence themselves. In a study of 45,000 ninth-graders Mr Pfeiffer conducted in 2007-08, those kids who had been beaten by their parents were five times as likely to commit repeated crimes or to use cannabis, and missed school four times more frequently for ten days a year or more.

Scandinavian countries, in part inspired by the children’s books of Astrid Lindgren, the author of the popular Pippi Longstocking (pictured) series, were the first to make spanking illegal for teachers in the 1950s and 60s. Between 1979 und 1983, they also outlawed spanking by parents. Crime rates, gun ownership and prison populations have been falling since.

By contrast, spanking is still common in large parts of America, especially in the Evangelical milieus of Southern states. This is also where crime remains relatively high, gun ownership common, and incarceration excessive. (America’s incarceration rate is between eight to ten times that of northern European countries.)

Within Europe, countries like Germany followed the Scandinavian example with a law against spanking in 2000, while others, like Britain, fall somewhere between Europe and America (as so often). Again, Mr Pfeiffer notices the expected correlations with crime and punishment.

Mr Pfeiffer also observes a connection between religion and child-spanking. Even in Germany, there is one tiny group where child-spanking is still common, and where increasing religiosity leads to more frequent spanking. This group subscribes to a brand of Protestantism similar to that practiced by white American Evangelicals. (By contrast, for mainline Protestants and Catholics in Germany, increased religiosity leads to a lower probability of spanking.)

In America in 2006-07, according to Human Rights Watch, more than 200,000 children were beaten by their teachers with a stick as a punishment. They overwhelmingly lived in the southern states and in Evangelical families. Two studies in 2010 showed that only 15% of American children are raised by their parents without any physical violence at all. To Mr Pfeiffer, this is one (of admittedly several and complex) factors, that explain why Americans own more guns, commit more crime and punish more severely than western Europeans. The conclusion, suggests Mr Pfeiffer, is that everybody, including Americans, should try raising kids with what he calls “Liebe statt Hiebe” (love instead of beatings).