Human evolution; our complex speech mechanism (Introduction)

by David Turell @, Tuesday, May 07, 2019, 20:15 (18 days ago) @ David Turell

With lots of research we still have no idea how the brain produces language:

"For all the sophistication of their ideas, surprisingly simple questions remain. Which part of our brain carries information forward in time? No one knows. For that matter, no one knows what a symbol is, or where symbolic interactions take place. The formal structures of linguistics and neurophysiology are disjoint, a point emphasized by Poeppel and David Embick in a widely cited study. There is an incommensurability between theories of the brain, TB, and theories of the mind, TM. This is the sort of granularity issue that concerned Poeppel and Embick. TM deals with formal devices and how they interact, while TB deals with waves of different frequencies and amplitudes, and how they overlap in time sequences across brain regions.


"Few neuropsychologists have studied how sentences break down into phrases, or how words carry meanings, or why speech is more than just sound. No one has distinguished one thought from another by dissecting brains. Neuroimaging tells us only when some areas of the brain light up selectively. Brain wave frequencies may suggest that different kinds of thinking are occurring, but a suggestion is not an inference—even if there is a connection between certain areas of the brain and seeing, hearing, or processing words. Connections of this sort are not nothing, of course, but neither are they very much. Is this because techniques have not yet been developed to target individual neurons? Or is it because thinking is more subtle than previously imagined?

We may not figure this out within our lifetimes.


"When Friederici writes about the “fast computation of the phonological representation,” an obvious inferential lapse is involved.4 Some considerable distance remains between the observation that the brain is doing something and the claim that it is manipulating various linguistic representations. Friederici notes the lapse. “How information content is encoded and decoded,” she remarks, “in the sending and receiving brain areas is still an open issue—not only with respect to language, but also with respect to the neurophysiology of information processing in general.”


"Cognitive scientists cannot say how the mass or energy of the brain is related to the information it carries. Everyone expects that more activity in a given area means more information processing. No one has a clue whether it is more information or more articulated information, or more interconnected information, or whether, for that matter, the increased neuro-connectivity signifies something else entirely. Friederici remarks:

"The picture that can be drawn from the studies reviewed here is neuroanatomically quite concise with respect to sensory processes and those cognitive processes that follow fixed rules, namely, the syntactic processes. Semantic processes that involve associative aspects are less narrowly localized.


If the perception of a signal presupposes some sensory modality, the modality must swing into action before computation begins. Language in Our Brain is written in the expectation, or the hope, that a division of labor into phonetics, morphology, syntax, semantics, and pragmatics more or less corresponds to the tasks the brain executes in aggregating representations from more elementary bits.


"There is also a language network at the molecular level. “Information flows,” Friederici writes, “from the inferior frontal gyrus back to the posterior temporal cortex via the dorsal pathway.” This is, of course, inferential: no one has seen information flowing, if only because no one has ever seen information. But brain events cohere at different levels into a pattern, which is consistent with what can be surmised from brain deficits and injuries. A functional language network, if more abstract than the digestive system, is no less real.


“'t is rather unlikely that psychology, on its own, will arrive at the real, lawful characterization of the structure of the mind, as long as it neglects the anatomy of the organ of the mind.” I am left wondering whether neurobiology shouldn’t have to take in all seriousness the central results of cognitive psychology—including the competence/performance divide—if seeking a lawful understanding of the human mind."

Comment: Presented to show just how difficult it is to research and understand the brain and the presence of mind. The enormous complexity demands to understand it was designed.

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