How the Stone Age was more about hurling words than rocks

Insults and metaphors may have characterised the earliest prehistoric human languages, according to a study by Antonio Benítes-Burraco at the University of Seville in Spain and Ljiljana Progavac at Wayne State University, Detroit, USA.

The classical technique used by linguists compares all languages currently spoken or recorded for similarities and differences, producing detailed trees and maps of how languages have evolved over time. But this method cannot reach back into prehistory beyond 10 thousand years ago and therefore cannot tell us about the very first human languages arising gradually as much as 200 thousand years ago or even earlier. Benítes-Burraco and Progavac have brought together work from linguistics, human evolution and psychiatry to shed light on how speakers of these very first languages communicated.

One of the key features of human thought and language is ‘cross-modality’: our ability to take two unrelated concepts and merge them into a new concept, often turning something concrete into something abstract. The familiar outcome includes figurative speech and metaphor. If I tell you that I am a ‘night owl’, you understand that I am not actually a bird. If I call you a ‘couch potato’, I do not really think you are a vegetable.

The ability to make new meaning that is more than the sum of the parts requires increased connectivity across the brain such as has occurred during human evolution. This in creased connectivity also enables the generation of ‘ideaphones’ that

“It may not seem like it, but rapid, reactive aggression appears to have 
decreased during human evolution”

use other senses, such as sound and shape, to convey meaning, for example, ‘tick-tock’.

In psychiatry, many conditions are associated with changes in the use of language. In some, like synaesthesia and schizophrenia, cross-modality is increased, while in others, such as autistic spectrum disorder, it is decreased. Alongside these changes in cross- modality, there tend to also be changes in reactive aggression, ie, aggression as a rapid response to a trigger.

In general, increased cross- modality tends to be associated with decreased aggression and this may reflect what happened during human brain evolution. It

may not seem like it, but rapid, reactive aggression appears to have decreased during human evolution, although sadly, premeditated aggression increased and is characteristically human.

A common substitute for physical aggression is to use verbal insults. All languages have a range of insults, such as ‘vivid compounds’, where two words, often a noun and a verb, are put together to give a negative meaning, for example, tattle- tale and cry-baby in English or muti-voda (‘muddy-water’, meaning trouble-maker) and vuci-guz (‘drag-butt’, meaning slow-moving person) in Serbian. These insulting vivid compounds employ similar mental, linguistic processes to creating metaphors.

Benítes-Burraco and Progavac propose that early prehistoric language evolution involved developing a fine balance between increasing connectivity between parts of the brain and inhibiting pathways in the brain that lead to reactive aggression. This is part of the gradual distancing of language processing from emotion in general, which enables a more considered use of language and the evolution of grammatical complexity.

The general reduction in reactive aggression mirrors the reduction in aggression seen in domesticated animals. Throughout human history, cultures have tended to put pressure on people to conform, co-operate and be less aggressive – resulting in a form of self-domestication.

Adding the modern-day evidence from a range of psychiatric conditions supporting a connection between brain connectivity, aggression and language, the resulting model of prehistoric language evolution proposes a feedback loop. In this model, increasing brain connectivity and decreasing aggression drive the emergence and use of figurative language, along with using verbal rather than physical aggression, which in turn accelerates the engine of cultural changes, such as self-domestication and further reduced aggression.

As Winston Churchill famously asserted: ‘meeting jaw to jaw is better than war’.

REFERENCE

• Benítes-Burraco, A. and Progavac, L. (2021) Language evolution: examining the link between cross- modality and aggression through the lens of disorders, Philosophical Transactions of the Royal Society B, 376: 20200188. https://doi. org/10.1098/rstb.2020.018