This is interesting: Why Are These 32 Symbols Found In Ice Age Caves Across Europe?
There is also a Ted Talk, but I haven’t watched it yet.
More information here:
The resulting study was an eye-opener: She found just 32 types of signs in use across the entire continent during the Upper Paleolithic period. “For there to be this much continuity between sites, I realized that our ancient ancestors had to have a system in place,” she writes. Moreover, the early diversity of geometric signs she had discovered in France was repeated across Europe. This suggested that modern humans had invented these signs long before they arrived in Europe—mostly likely in their African homeland.…the Ice Age signs were far from meaningless, she says. Some markings, such as the meandering lines that von Petzinger spotted at a site in Portugal’s Côa Valley region, may have been maplike representations of a river or other landscape features. Other signs, such as the lines inscribed on the deer-tooth necklace, could have served as memory aids for ceremonialists presiding over important rituals or recounting a tribe’s origin stories. Such markings, says von Petzinger, seem to be a way of storing information externally—a form of graphic communication that eventually led to writing.
I’ve been paying closer attention to prehistoric cultures after reading The Memory Code, which I highly recommend reading.