Scientists who study speech in humans think this ability must have arisen in our brains as we evolved from primates, but they don’t know exactly how. These researchers can compare the human brain with other primate brains to see how it changed during evolution to confer human speech.
Previous researchers have suggested structures in the front part of primate brains, like groove patterns, could have helped humans learn to speak.
The scientists looked at one specific part of the brain that controls speech, facial expressions, and language, called the prefrontal extent of the frontal operculum, or PFOp for short. They explained the PFOp is part of a structure that covers the inner parts of the brain, called the operculum. They found the PFOp was fully developed in humans, only partially developed in chimpanzees, and absent in old-world monkeys.
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The scientists concluded changes in the operculum and brain groove structures helped humans learn to speak, but questions remain. They cautioned that they could not link any specific function of the PFOp to the development of human speech. Thus, they suggested future researchers should determine how the PFOp functions within the human brain to identify this link.
