A recent post at mindmatters.ai summarizes the results of a recent study (see abstract here) by Dutch and British researchers comparing the brains of chimpanzees and humans. According to mindmatters.ai, the study found that "connections between language areas in the human brain are much larger than previously thought and quite different from those of the chimpanzee brain." The "language areas in the human brain" are Broca's area, which is involved in the production of speech, and Wernicke's area, which enables understanding of written and spoken language.
Why are the results of this study of interest? Well, for one thing, they would seem to make an evolutionary explanation of human language less plausible. Here is why. It is claimed that humans and chimpanzees had a common ancestor millions of years ago. Consequently, any differences between the brains of modern-day humans and chimpanzees would be the result of different evolutionary paths for the two species. Furthermore, it seems reasonable to assume that specific the differences between chimpanzee and human brains identified by the study--differences that would seem to help explain the human capacity for language--would have required some fairly significant changes in the structure of the human brain over time. Such changes would have, in turn, necessitated a fairly large number of gene mutations. Such mutations would have needed to be essentially simultaneous--because piecemeal mutations would not have bestowed any new capacity beneficial to humans for natural selection to select. However, as Casey Luskin at discovery.org notes in discussing a 2008 study on gene mutations in humans by mathematicians Rick Durrett and Deena Schmidt:
After calculating the likelihood of two simultaneous mutations arising via Darwinian evolution in a population of humans, they found that such an event "would take >100 million years." Given that humans diverged from their supposed common ancestor with chimpanzees only 6 million years ago, they granted that such mutational events are "very unlikely to occur on a reasonable timescale" (emphasis mine).
If only two simultaneous gene mutations would have taken over 100 million years to occur, the likely more numerous mutations required to bring about the structural differences between chimpanzee and human brains we are discussing are unlikely to have occurred within a period of only 6 million years. Thus, an explanation citing evolution as the reason why humans have a capacity for language and chimpanzees (or other primates) don't seems much less credible.
In short, the discovery of clear differences between the brains of chimpanzees and humans is yet another problem for any attempt to explain the human capacity for language as being the result of Darwinian evolution.
Note: For some previous blogposts on the topic of evolution and human language, see here, here, and here.
Image of chimpanzee from Wikimedia Commons