Mammal brains, unlike bones, do not fossilize. This fact presents a conundrum for scientists trying to understand how we came to be how we are.
For example, scientists have long argued over how humans became able to speak — if only they had an ancient brain to settle the debate!
But with no time machine, scientists must resort to what they have available, like the brains of animals today that closely resemble the long-extinct ancestors to us. Modern animal brains can open the door to history, and scientists use them to infer the workings of ancient minds.
And so, in a new study, researchers in the United Kingdom have come to posit something rather spectacular about the very old brain: The origin of language in the brain is 20 million years older than we thought. That’s quite a sizeable jump from the 5 million-year-old guess of earlier studies.
In their research, scientists analyzed open-source brain scans and conducted their own scans on humans, monkeys, and apes. They “identified homologous pathways originating from the auditory cortex,” state teh authors in their study, which was published Monday in the journal Nature Neuroscience.
While speech and language are exclusively human, the presence of this pathway in the brains of members of the monkey species suggests an evolution took place much earlier than we thought. Scientists assumed this pathway developed in the human brain 5 million years ago (when humans last shared an ancestor with chimps, members of the ape species). However, new observations across all three species (monkeys, apes, humans) date the emergence of the neural pathway to back to when humans last shared an ancestor with the macaque monkey, which was at least 25 million years ago.
Read more: Inverse