Why do people talk?

The neural connections behind language.

Perhaps a unique human skill is distinguishing which complex sounds are used for communication. The part of the human brain that corresponds to sound is the auditory cortex located in the temporal lobe, and some of its neural circuits can respond specifically to human voices rather than other sounds.

However, such circuits also exist in nonhuman primates and even dogs. "These data suggest that primate auditory systems evolved quasi-linguistic sophistication long before the evolution of human language," Fitch wrote.

If human language ability does not originate from hearing, then perhaps it originates from vocalization. Unlike those depicted in "Planet of the Apes," nonhuman primates can only produce murmurs rather than nuanced speech. But it's not obvious why, because human vocal cords have been around for 70 million years and are roughly the same as those of most mammals.

Even a low-lying larynx is not unique to humans. Moreover, this anatomical adaptation is not entirely designed for complex vocalizations. Experiments have found that some primates also have vocal cords that can move flexibly.

Fitch writes:

“The human ear is not significantly different from the ears of other primates. Long before humans evolved language, our primate ancestors Peripheral hearing has developed."

Perhaps speech perception requires "vocal tract normalization," the ability to recognize the same word produced by different sounds (for example, in a child's voice). voice and say the same sentence in an old man's voice). However, this ability to recognize is not unique to humans. The trained guinea pigs can recognize vowels when listening to speech, regardless of whether the speech comes from a male or a female.