by Kaitlyn MayFriederici (2017) provides a comprehensive review of research exploring the evolution of language. By reviewing structural and functional neuroanatomical differences between the primate and mature human brain, as well as comparisons between the phylogenesis and ontogenesis of language-relevant brain structures, Friederici provides a relevant timeline of the neural basis of language evolution while highlighting the specific aspects of language and neural structures which underpin this ability.
Friederici begins with a brief overview of the differing ways in which researchers define language. This then moves into a complex discussion of the computational mechanisms for human language. Though this section may be a bit daunting to those who are not well-versed in the language literature, Friederici does an admirable job breaking down difficult topics. Essentially, some researchers define language as all aspects of communication (facial expressions, hearing language, processing, etc.) while others focus specifically on the computational mechanisms behind how language is built. It is this construction aspect, and the complications of advanced grammar, that separates nonhuman primates from humans. Friederici then begins reviewing studies of the neural mechanisms of human language. These studies overview differences in acquiring grammar systems in human and nonhuman primates, as well as the neurobiological bases of these grammar types. These studies conclude that the ability to master phrase structure grammar is uniquely human. Moreover, these studies highlight the neural mechanisms of language processing. Friederici first overviews the role of the posterior portion of Broca’s area (Brodmann area [BA 44]) in not only syntactic hierarchy building, but in the evolutionary pathway of language. Next, Friederici discusses the role of the inferior frontal gyrus, posterior temporal cortex, and the white matter fiber bundles connecting them to processing syntactically complex sentences. The paper then moves into a review of cross-species comparisons of language. To date, there is no evidence that other species can process and learn hierarchically structured sequences. Friederici begins by noting that the posterior temporal cortex is larger in the left than the right hemisphere of both the human and chimpanzee brain, reflecting the left lateralization of language. In contrast, Broca’s area demonstrates distinct differences between cytoarchitecture, asymmetry, and developmental trajectories of human and nonhuman primates. Moreover, the dorsal pathway, a crucial pathway for the language ability in adult humans, is much weaker in nonhuman primates than in humans. These differences are postulated to reflect the behavioral trajectories in child language development as well as the lack of these behaviors in nonhuman primates. Friederici concludes that the differing asymmetries may be crucial to understanding the evolution of language. Friederici (2017) provides an in-depth review to the neural circuits underlying the evolutionary pathway towards human language. Although does an excellent job reviewing a large body of relevant studies, the author neglects to include studies which indicate abilities of nonhuman primates to acquire human language skills, such as those in which chimpanzees learn to use American Sign Language (ASL). Although these studies typically admit limitations in the nonhuman primates abilities, they are still noteworthy to the evolution of language. Still, what Friederici does do nicely is provide a comprehensive understanding of the exact piece of language which is distinctly human—the ability to process and learn hierarchically structured sequences. Reference: Friederici, A. D. (2017). Evolution of the neural language network, Psychonomics Bulletin and Review, 24, 41-47.
3 Comments
Vanessa Marshall
1/30/2019 09:00:45 am
I read your blog before reading the article. It really helped set me up for the format of the paper because there is a lot of technical jargon that can easily overwhelm someone unfamiliar with brain biology. That said, it was an awesome article. I really liked how the differences between humans and non-human primates' brains was laid out and then applied to language. It was heavy on the biology side, but the language applications made this article prime for anthropological uses.
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Vanessa Marshall
2/27/2019 09:46:25 pm
After gaining a better idea of what Neuroanthropology looks like experimentally through reading more papers, I am still not convinced that Friederici really makes use of anthropologically data. That said, the data provided is still very good, and like Seligman and Brown wrote about with the cultural embodiment of emotional words, I think a front loading concept can be used to introduce ethnographically relevant situations into this research to better understand how these evolutionary neural language networks are affected by culture. The interspecies comparisons provide plenty of biological data, and it might even be beneficial to front load social situations onto an experiment with nonhuman primates to compare results with humans.
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10/14/2021 02:44:08 am
i really enjoyed reading this article, it has a lot of valuable info it's the first time to know it, thanks for sharing
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AuthorThis blog is group authored by Dr. DeCaro and the students in his ANT 474/574: Neuroanthropology. Archives
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