Inthe days following the January 6 insurrection, many people tried to make sense of how and why this event came to pass. Ronan Farrow, writing in The New Yorker, discussed the role that far-right militia members played in the storming of the Capitol.

Among the “Oath Keepers, the Three Percenters, the Proud Boys, and the Boogaloo Bois” he described and interviewed, Farrow came across a particularly unusual find: a modern-day adherent of phrenology, the 19th-century science of judging faces and fates by the shape of the skull. Middle-aged former marine and professed Oath Keeper Donovan Crowl, with whom Farrow conducted a lengthy interview, “said he believed in phrenology” and only agreed to be interviewed after “examining pictures of my [Farrow’s] head.”

Of all of the aspects of Farrow’s reportage, it was this fact that made the internet’s day. Twitter was flooded with alternately horrified and joking comments about Crowl’s phrenological leanings.

As a historian of phrenology with a brand-new book out on phrenology and crime, I was tagged in many of these posts, which were shared with me by friends and colleagues. Yet while many internet commentators expressed surprise or amusement at this phrenological connection, nothing about these developments surprised or amused me at all.

Phrenology was a 19th-century science that originated in Continental Europe, developed by physicians and anatomists Franz Joseph Gall and Johann Gaspar Spurzheim, and was later popularized in the Anglo-American world by Scottish lawyer George Combe and in the United States by a number of physicians, professors, lawyers, and eventually self-named “practical” phrenologists, particularly the Fowler brothers, Orson and Lorenzo.

The science purported to use the evidence of the surface of the skull to determine a person’s character and potential, for both good or ill.

There are two crucial things to note about phrenology.

First, its originators and early promoters in Europe and in the U.S. were by and large intellectual elites, members of the professions of medicine and the law in particular. When it was first introduced, it was taken quite seriously as a science, promoted by such figures as the presidents of Yale and Harvard.

While it did eventually lose this status, as learned men turned away from it and it became a pastime for the masses, this was not before phrenology came to shape both social and political spheres. One example I discuss in my book is how phrenological language and assumptions helped shape 19th-century assumptions about criminality and criminal responsibility, including the notion of criminal insanity and the possibility for criminal reform.

Second, even when phrenology was considered to be a potentially “serious” science, it was never neutral — no science ever is.