With its ability to pass down complex information across many generations, human language is what makes us so distinct within the animal kingdom. Language almost certainly played a sizable part in humans' ability to become a dominant, if not the dominant species, on the planet.
Despite this, we know precious little about how human language evolved. A paper published the February 2018 issue of Frontiers of Psychology proposes that we should look at ancient cave art to gain insights into how our ability for language came to be.
"It's very difficult to try to understand how human language itself appeared in evolution," MIT linguist professor and the paper's lead author, Shigeru Miyagawa, told MIT News. "We don't know 99.9999 percent of what was going on back then.
"There's this idea that language doesn't fossilize, and it's true, but maybe in these [cave drawings], we can see some of the beginnings of homo sapiens as symbolic beings."
Art, acoustics and language
What Miyagawa and his co-authors, Cora Lesure, a Ph.D. student in MIT's Department of Linguistics and Vitor A. Nobrega, a Ph.D. student in linguistics at the University of São Paulo, propose is that cave paintings exist at the intersection of communication between visual and aural cues, or, as the academics call it in the paper, a "cross-modality information transfer."
Where the linguists get their hypothesis from comes from the fact that many of the caves in which art has been found are acoustic "hot spots." In these caves, sounds echo louder and more intensely the deeper one goes. Many of the drawings are located in these sections of the cave and, for the many different scientists, would seem to indicate that the sounds are the primary reasons the drawings are there; even some areas that would've been better for drawing on the walls were ignored in favor of these spots. The drawings would then depict sounds that humans made while in the caves.
Think about how many examples of cave art we know of — regardless of where the cave is located — that depict various four-legged animals, including horses. The reverberation of noises, be it tapping on rocks inside the cave or thunder from outside the cave, would have created sounds not unlike hooves galloping across the ground.
This blend of sound sound and visual representation, they write, "allowed early humans to enhance their ability to convey symbolic thinking to their conspecifics [fellow homo sapiens], as well as their ability to process acoustic and visual input as symbolic (i.e., to associate acoustic and visual stimuli to a given mental representation)."
The key concept to take from this is symbolic thinking. Such thought processes could have led to developing other types of communication, including sentences. The authors of the paper contend that this ability to work at the intersection between different stimuli would have given them an edge in their societies and that, in turn, would have allowed the trait to be passed on to other generations.
"We hypothesize that the individuals who were able to transform symbolic thinking into sensory stimuli — likely privileged in the society — may have had a higher rate of reproductive success, thus spreading the cognitive ability required for this practice through the population."
Basically, being artistic may have always been a good way to meet someone.
More work needed
Of course, this a hypothesis that Miyagawa, Lesure and Nobrega are putting forth, not a declarative statement or study that this was, in fact, how our language skills developed. Their paper relies on work from archaeoacoustics (archaeologists who study the mechanics of sound), art historians and other linguists as a foundation on which to build their case.
As with all such hypothesis, a great deal more research is required before anything can be said in a definitive way. This will include, Miyagawa explained to MIT News, a closer look at the visual syntax of cave art from around the world and to determine just how much of the art can be interpreted in linguistic terms.
One thing Miyagawa does feel confident about regarding his team's hypothesis is that it will further conversations about the importance of our art in our development as a species.
"If this is on the right track, it's quite possible that … cross-modality transfer helped develop a symbolic mind," Miyagawa said. It would mean that "art is not just something that is marginal to our culture, but central to the formation of our cognitive abilities."