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Hominid Dominion via a Neocortical Quadrupling: The Neuronal Stepping Stones of Language
Poster Session D, Saturday, September 13, 5:00 - 6:30 pm, Field House
Donald O'Malley1, Weslyn Cai1; 1Northeastern University
HOMINID DOMINION: The quadrupling of chimpanzee neocortex (in hominids) is as powerful as it is mysterious. Each billion-neurons added had to confer immediate adaptive advantage: extra-bulbous heads and metabolic profligacy would not cut it on the African savannah. But we know scant details of language evolution: neither the how nor the why of our tremendous increase in cognitive capacity. The world of knowledge that humans can easily acquire today dwarfs chimp cognition: animals write no dictionaries. While language and writing are humanity’s defining features, we have direct access only to the surface structure of human cognition: sentences. This linguistic capacity, however, is but a thin veneer that distracts from the opaque mystery of where thoughts (and eventually sentences) truly come from. LEVO: Language evolution most likely began early in the quadrupling and thereafter tracked the increasing skills and dominance of savannah hominids (Bickerton and Szathmary, 2011). We previously sketched a set of neuronal circuits needed to progress from proto-words to fully modern language/FML (O’Malley and Xue, 2025). This Neuro-Generative Grammar deploys: a linguistic-symbolic layer (elaborated by the arcuate fasciculus), Tag-Sequence Read-Out machinery, an expanded working-memory dedicated to symbolic sequences, Pattern Recognition Machinery (for morphosyntax), a Syntactic Translation System (STS; to translate semantic constructs into sentences) and Language-Chunk Assembly Circuits (for long-distance dependencies and such; part of STS). Roughly 15 billion neurons were added providing new neural territory within which to duplicate ancestral sequencing and pattern-recognition modules which could then be adapted in service of sentence production, sentence comprehension and the STS. Despite the quantity of new neural machinery required to traverse the proto-words to FML divide, language is just the tip of our Cognitive Iceberg. COGVO: Herein Cognitive Evolution refers to the new cognitive machinery required for the progression of hominid cooperation, coordination and technology—beginning 2.5 million years ago with power scavenging and the Oldowan Industry. Words, in this context, are ultra-compact designators of rich semantic worlds. “Tool” is just an arbitrary pattern of three phonemes but one could write for hours about tools of every sort (stone, carpenters, scientific, auto-mechanics and so on). Similarly, the sentence “Choose the right tool” could be part of myriad semantic situations. We suggest that linguistic complexity might be a 20-dimensional or 50-dimensional space, in terms of the numbers of distinct syntactic constructs, arrangements and major rules needed (for morphosyntax, inflection, schemas and such). In contrast, semantic items operate in a 500-D or 1000-D semantic space, via the connectivities between semantic auto-associative networks. Some high-dimensional notions, lurking within our sub-conscious information processors, can be difficult to put into words. CO-EVOLUTION: We posit an early accrual of neuronal circuits that ultimately led to a massive semantic-constructive capability: it is impossible to teach theology to dogs or thermodynamics to chimps. Advanced thought-machinery required a co-evolving linguistic capacity aka our Language-Learning Organ (LLO). While our genetically-encoded LLO does not encode specific syntactic rules, it does constitute a Universal Grammar—a set of universal neuronal circuits that allows all hominids (and only hominids) to create and learn languages.
Topic Areas: Language Production, Meaning: Lexical Semantics