The calls of our closest evolutionary cousins still hit an old target in the human brain. The “call of the wild” remains deeply ingrained in the human brain.
When you hear a jungle monkey howling through the treetops, what do you really hear? If a chimpanzee is responsible for the racket, this sound could trigger a ancient form of recognitionflickering below the threshold of our consciousness.
This is the conclusion of a new study by researchers at the University of Geneva, who observed that chimpanzee calls activate a specific region of the human brain sensitive to voice, the so-called “temporal area of the voice” (TVA), which was thought to answer only to the voices of our own kind.
The results of the , recently published in the journal eLifesuggest that certain vocal recognition capabilities may be shared between species and be prior to language itself humana.
“When participants heard chimpanzee vocalizations, the response was clearly distinct from that elicited by bonobo or rhesus monkey vocalizations,” he says. Leonardo Ceravoloneuroscientist at the University of Geneva and co-author of the study, at the university.
Four species of primates The following participated in the study: humans, chimpanzees, bonobos and rhesus monkeys.
Ceravolo and colleagues gathered 18 vocalizations of each of the four species and presented them randomly to 23 human participantsasking them to play a kind of auditory “who is who”identifying the species behind each scream.
In parallel, they monitored the participants’ brain activity using magnetic resonance imaging, while they listened to the sounds and analyzed the vocalizations using statistical modeling to understand How did they differ acoustically?.
The results obtained by the researchers were surprising. Participants’ brains “light up” when processing the chimpanzees’ calls: TVA regions responded in a more marked way to these sounds than those of other non-human primate species.
The researchers further found that the positive social vocalizations of chimpanzees, but not those of bonobos, were acoustically the most similar to positive human voices.
The findings align with previous work suggesting that the communication patterns of bonobos, our more peaceful evolutionary cousins, evolved separately over timedespite the fact that we are genetically as close to bonobos as we are to chimpanzees.
Primate vocalizations included isolated calls or sequences of calls, of threat and anguish as well as positive social sounds.
The 15 chimpanzees were recorded in the wild in Budongo forest, Uganda, while the 10 bonobos were recorded in the wild, in Salonga National Park, in the Democratic Republic of Congo. The 16 rhesus monkeys were recorded in semi-free conditions on the island of Cayo Santiago, in Puerto Rico.
Previous studies had already analyzed the how the human brain reacts not only to primate calls, but also to feline calls.
However, until now, no work had identified specific responses between species on área TVA humanathe authors emphasize. Future research could isolate the acoustic “fingerprints” that distinguish chimpanzee calls from bonobo calls.
“We already knew that certain areas of the brain of animals reacted in a specific way to the voices of their counterparts”, adds Ceravolo. “But here we show that a region of the adult human brain, the anterior superior temporal gyrus, is also sensitive to non-human vocalizations”.
Apparently, the “call of the jungle” remains well entrenched deep in the human brain.
