Complicated language and speech are considered unique to humans. And the neural pathways responsible for speech appeared in the brain of our ancestors about 5 million years ago, after the separation of the evolutionary lines of humans and chimpanzees. However, recent research has pushed this theory, which has existed for many years, twenty million years ago.
A new scientific work by British scientists indicates that the brain structures responsible for speech appeared in non-human apes 25 million years ago.
The team, whose work was written by Inverse, studied publicly available data on the structure of the brain of people, as well as human and non-human monkeys. Then the scientists conducted their own experiments on scanning the brain of humans, chimpanzees and macaques.
The researchers’ task was to find (arcuate fasciculus) – the neural pathway that connects Brock’s zone and Wernicke’s zone (these parts of the brain are responsible for different aspects of speech). It was previously established that chimpanzees have a similar structure, which they inherited from a common ancestor with humans (in biology this is called a homologue). However, it was still unclear whether an arcuate bundle or its homologue was present in the brain of non-human monkeys.
A study of the results obtained by scanning the brain confirmed that macaques have their own version of the arcuate beam. Given the time of the difference between the evolutionary lines of humans and macaques, this means that this structure arose about 25 million years ago.
Perhaps studies of other species of primates will push the date of its appearance even deeper into the past. This, of course, does not mean that a complex language existed many millions of years ago – in this case we are only talking about the anatomical prerequisites for its appearance.