Language is one of the most important human adaptations, underpinning much of our species' success. However, this makes it rather tricky to study its evolution. After all, it offers so many benefits how can we figure out which one (or ones?) drove it's evolution? Particularly given the earliest examples of language have long since vanished.
A recent experiment has concluded the key benefit of language may be teaching 1. Prior to this, the social benefits of language were considered more important factors in its evolution.
Teaching seems like an obvious benefit
Yes, the ability to pass on information that could aid in your survival does seem like an obvious way language could aid in your survival. So why wasn't teaching considered the driving force of language earlier? To be fair it was. People just thought of it as a relatively minor factor; with the social benefits being more important in it's evolution.
This is because when you look at how modern people use language, it's most often used for socialising, bonding and so forth. We're social animals and keeping the bonds between us strong is of the utmost importance. We devote relatively little of our linguistic energy to teaching2. In fact, when you look at our close relatives we see a similar pattern; with most of their interactions reinforcing social bonds rather than teaching 3.
Additionally, at some point our ancestors would have encountered a "socialising shortfall." Primates traditionally bond through grooming, but can only groom one other chimp at a time. This places a limit on how big their groups can be before they can't groom each other enough to stay friends. We live in groups larger than this limit, meaning we needed to develop something that could allow us to socialise a lot more efficiently. Enter language.
So this new study...
A new experiment asks us to reconsider all that by demonstrating just how incredibly useful even a little bit of language can be to teaching. They tried to teach a bunch of palaeolithic newbies how to make the stone tools our ancestors created; varying the amount of language, imitation etc. that was allowed per class 1.
Increasing the complexity of the teaching allowed obviously increased their success rate at making flakes; but language often blew the other approaches out the water. Depending on how they measured success (quality of tools, number of tools etc.) verbal teaching doubled productivity compared to imitation. Compared to the most complex teaching before language (gestural teaching) improvements of 20 - 50% were often seen 1.
They argue that these benefits are so significant that evolution wouldn't have ignored them. Sure, socialising may have kicked off the evolution of language (and likely continued to influence it) but soon after the benefits of teaching would also begin to drive it's development 1.
Crucially, they also show that this drive would have existed in the earliest stone tools; suggesting the evolution of language may have begun around the time they started to be made: 2.4 million years ago. And those tools may have been made by our more ape-like ancestors, the Australopiths. Were they those apes the first to take steps towards speaking?
So can we forget about sociality?
No. This discovery isn't incompatible with previous ideas (which have a fair amount of evidence behind them anyway, so can't be easily dismissed). Evolution is a complex thing and it's likely many factors drove and influenced the evolution of language. This research simply adds one more to the pile.
Although it does have an interesting implication: if teaching is driving the evolution of language, could our focus on old languages be holding it back? Clearly, it's time we took Shakespeare out of schools, for the good of the species.
References
- Morgan, T. J. H., Uomini, N. T., Rendell, L. E., Chouinard-Thuly, L., Street, S. E., Lewis, H. M., ... & Laland, K. N. (2015). Experimental evidence for the co-evolution of hominin tool-making teaching and language. Nature communications, 6.
- Mesoudi, A., Whiten, A., & Dunbar, R. (2006). A bias for social information in human cultural transmission. British Journal of Psychology, 97(3), 405-423.
- Dunbar, R. I. (2003). The social brain: mind, language, and society in evolutionary perspective. Annual Review of Anthropology, 163-181.
