Though the term “manspreading” entered the English lexicon around 2014, a German feminist photographer was onto the idea as early as the 1970s. And she compiled what “may be the most exhaustive study of manspreading ever conducted,” the Pacific Standard reports.

Between 1972 and 1977, Marianne Wex photographed men, women and their posture. Her finished book, published in 1979, includes nearly 5,000 images and is entitled Let’s Take Back Our Space: Female and Male Body Language as a Result of Patriarchal Structures.

Taking up too much space on the train isn’t just annoying, some feminists argue; it’s an expression of male privilege and female inequality, based on the assumption “that men require (and are allowed) more space,” the Pacific Standard summarizes.

In service of this argument, it cites not only Wex’s photographs but also the writings of Raewyn Connell, an Australian sociologist who came up with the idea of “hegemonic masculinity.”

Then again, empirical evidence shows that men do actually take up more space than women. They’re about 15 to 20 percent bigger, one study found. Moreover, that size difference has grown bigger over history. Our early ancestors were much closer in size, regardless of gender.

At very least, though, Wex’s book is an interesting study in body language. The English-language version of Wex’s book retails for $170—but you can also watch it on YouTube, though the pictures are pretty small.