You may have heard that men and women have some subtle differences in morphology — there is considerable variation and overlap, of course, but there are discernable patterns. It’s not just the obvious breasts and shoulders and hips, either, but, for instance, slight differences in the hands. Men tend to have ring fingers that are longer than their index fingers, while those two fingers in women are of approximately equal length. Which makes it interesting that many Paleolithic cave paintings include tracings of the artists’ hands.
You can see where this is going. We should measure digit lengths in these stencils!
Archaeologist Dean Snow of Pennsylvania State University analyzed hand stencils found in eight cave sites in France and Spain. By comparing the relative lengths of certain fingers, Snow determined that three-quarters of the handprints were female.
"There has been a male bias in the literature for a long time," said Snow, whose research was supported by the National Geographic Society’s Committee for Research and Exploration. "People have made a lot of unwarranted assumptions about who made these things, and why."
There need to be massive caveats to the interpretation of the data. In modern populations, variation and overlap means that assessments of sex from digit lengths only has 60% accuracy, which is terrible — I checked out my own hands with a crude visual inspection, and by my right I’m a woman, by my left I’m a man, and both have very slight differences. Their sample size is also very small: 32 hands that were clear and sharp enough to measure. But at the same time, they report that the degree of sexual dimorphism in the hands was much greater than is seen in modern populations Well, maybe: I’d like to see the dimorphism data for modern hunter-gatherer populations, in particular from African populations with their greater genetic diversity. Also, you can’t call it sexual dimorphism if you don’t have an independent measure of the sex of the handprints. Maybe there was greater non-sexual variation in hand shape and, for instance, women made all of the stencils, but 15,000 years ago 25% of women had “man hands”.
Still, at least the data says that the cave painters were more diverse than expected, which fits better with a hypothesis that both men and women were active participants in these surviving, visible aspects of Paleolithic culture.