The evolution of language systems in the human brain

Preparation

  • Consider this quote:

The details of the motor programs instantiated in the motor cortex likewise are phenotypically acquired. Given the architectural similarity of the cortical-striatal-cortical circuits implicated in motor control and cognition noted earlier, it is most unlikely that the cognitive “pattern generators” that specify syntactic operations are innately specified. The neural mechanisms implicated in motor control are massively parallel, and cannot usefully be described by means of sequential algo- rithms similar to those commonly used by linguists to describe the “rules” of syntax.  … [T]he inability of formal linguistics to describe the sentences of English, arguably the most intensively studied language on earth, may derive from an overreliance on algorithmic procedures that do not take account of graded semantic and “real-world” knowledge. Even formal linguists committed to the Chomskian school … note that it has not been possible to describe the syntax of English by these procedures. The problem most likely rests in the fact that language is the product of a biological brain that does not resemble the digital computers programmed by means of sequential algorithms that linguists implicitly use as a model of the mind.   (Lieberman, 2002; citations removed for readability).

  • And watch this short video

 

Close reading and peer-to-peer discussion

What is the oldest physical evidence for human language?

Is the “call system” in non-human primates homologous to the “language faculty” in humans?

Complex bird song arose 3 times independently.  What is the significance of this fact for our discussion of the evolution of human language?

What do you make of Deacon’s comment that “there is to date no evidence for a specific neuroanatomical substrate for universal grammar”?

Class discussion

Class will meet via Zoom video conference at the normal time.  A few minutes before 11:00am, please join the class using this stable URL:  https://cwm.zoom.us/j/674322161

Response

The neural bases of human linguistic ability are complex, involving structures other than Broca’s and Wernicke’s areas. … [M]any other cortical areas and subcortical structures form part of the neural circuits implicated in the lexicon, speech production and perception, and syntax. The subcortical basal ganglia support the cortical-striatal-cortical circuits that regulate speech production, complex syntax, and the acquisition of the motor and cognitive pattern generators that underlie speech production and syntax. They most likely are involved in learning the semantic referents and sound patterns that are instantiated as words in the brain’s dictionary.  …  Some aspects of human linguistic ability, such as the basic conceptual structure of words and simple syntax, are phylogenetically primitive and most likely were present in the earliest hominids. Speech production, complex syntax, and a large vocabulary developed in the course of hominid evolution, and Homo erectus most likely talked, had large vocabularies, and commanded fairly complex syntax. Full human speech capability, enhancing the robustness of vocal communication, most likely is a characteristic of anatomically modern humans.
The computational architecture and neurophysiology of the human brain and comparative evidence suggest that neural systems that enhanced adaptive motor control may have been the starting point for the evolution of human speech and complex syntax. Given the involvement of the basal ganglia in the cortical-striatal-cortical circuits regulating upright bipedal locomotion, one of the first derived hominid features, adaptations aimed at enchancing walking may have initiated the process that yielded the neural bases of human linguistic ability.  (Lieberman, 2002; citations removed for readability).

Further reading

Lieberman, P. (2009). Human language and our reptilian brain: The subcortical bases of speech, syntax, and thought. Harvard University Press.   [Amazon]

Lieberman, P. (2001). Human language and our reptilian brain–the subcortival bases of speech, syntax, and thought. Perspectives in Biology and Medicine, 44(1), 32-51.  [PDF]

Lieberman, P. (2002). On the nature and evolution of the neural bases of human language. American Journal of Physical Anthropology: The Official Publication of the American Association of Physical Anthropologists, 119(S35), 36-62.    [PDF]

Robert C. Berwick and Noam Chomsky.  Why Only Us: Language and Evolution.  MIT Press. 2017.