Printing and imitation were identified as triggering factors in the witch hunts.

In previous academic works, the intensification of witch hunts in Europe was linked to the rise of economic hardships, famine, and social tension amidst crop failures, wars, and epidemics of plague and syphilis that occurred from the late 15th to the mid-17th centuries. The transfer of witchcraft cases from ecclesiastical courts to secular ones also contributed to the increase in the scale of persecutions. These reasons were mentioned, in particular, by medieval historian Grigory Bakus in a recent extensive interview about the witch hunts for Naked Science.

In a new study dedicated to this dark chapter of European history, a group of sociologists from Chapman University and Yale University, along with colleagues from the Santa Fe Institute (in the USA), examined other triggers beyond environmental and economic factors. The article was published in the journal Theory and Society.

The researchers proposed that the wave of repression against witches may have been initiated by the invention of the printing press and the beginning of book printing in Europe. With the emergence of printing houses, ideas about witchcraft, which were previously accessible to a relatively narrow circle of people, such as theologians and inquisitors, began to spread more rapidly among the general public.

One of the infamous publications of that time was the treatise on demonology and proper methods for prosecuting witches, "Malleus Maleficārum," written by the Dominican inquisitor Heinrich Kramer (the Latinized version of the name is Henricus Institor).

As noted by the study's authors, this work became both a theoretical and practical guide that local authorities relied on to identify, interrogate, and prosecute those suspected of practicing black magic.

In search of evidence for their hypothesis, the American scientists collected data on the time and place of the publications of "Malleus Maleficārum" and other similar texts, and then compared them with information about witchcraft trials in 533 cities of Central Europe from 1400 to 1679. The analysis showed that the release of books coincided with an intensification of persecutions.

Another key factor the researchers identified was the social and trade connections between cities and the tendency to emulate one another. When the methods described in Malleus Maleficārum were applied in one city, neighboring cities often learned about it and frequently repeated the experience.

“Cities did not make decisions [about persecutions] in isolation. They observed how their neighbors acted and learned from these examples. The spread of new ideas about witchcraft from books, combined with the judicial practices of neighboring cities, created ideal conditions for more widespread trials against witches,” explained one of the article's authors, Kerice Doten-Snitker (Kerice Doten-Snitker).